linux-stable/fs/ntfs/attrib.c
Mel Gorman 2457aec637 mm: non-atomically mark page accessed during page cache allocation where possible
aops->write_begin may allocate a new page and make it visible only to have
mark_page_accessed called almost immediately after.  Once the page is
visible the atomic operations are necessary which is noticable overhead
when writing to an in-memory filesystem like tmpfs but should also be
noticable with fast storage.  The objective of the patch is to initialse
the accessed information with non-atomic operations before the page is
visible.

The bulk of filesystems directly or indirectly use
grab_cache_page_write_begin or find_or_create_page for the initial
allocation of a page cache page.  This patch adds an init_page_accessed()
helper which behaves like the first call to mark_page_accessed() but may
called before the page is visible and can be done non-atomically.

The primary APIs of concern in this care are the following and are used
by most filesystems.

	find_get_page
	find_lock_page
	find_or_create_page
	grab_cache_page_nowait
	grab_cache_page_write_begin

All of them are very similar in detail to the patch creates a core helper
pagecache_get_page() which takes a flags parameter that affects its
behavior such as whether the page should be marked accessed or not.  Then
old API is preserved but is basically a thin wrapper around this core
function.

Each of the filesystems are then updated to avoid calling
mark_page_accessed when it is known that the VM interfaces have already
done the job.  There is a slight snag in that the timing of the
mark_page_accessed() has now changed so in rare cases it's possible a page
gets to the end of the LRU as PageReferenced where as previously it might
have been repromoted.  This is expected to be rare but it's worth the
filesystem people thinking about it in case they see a problem with the
timing change.  It is also the case that some filesystems may be marking
pages accessed that previously did not but it makes sense that filesystems
have consistent behaviour in this regard.

The test case used to evaulate this is a simple dd of a large file done
multiple times with the file deleted on each iterations.  The size of the
file is 1/10th physical memory to avoid dirty page balancing.  In the
async case it will be possible that the workload completes without even
hitting the disk and will have variable results but highlight the impact
of mark_page_accessed for async IO.  The sync results are expected to be
more stable.  The exception is tmpfs where the normal case is for the "IO"
to not hit the disk.

The test machine was single socket and UMA to avoid any scheduling or NUMA
artifacts.  Throughput and wall times are presented for sync IO, only wall
times are shown for async as the granularity reported by dd and the
variability is unsuitable for comparison.  As async results were variable
do to writback timings, I'm only reporting the maximum figures.  The sync
results were stable enough to make the mean and stddev uninteresting.

The performance results are reported based on a run with no profiling.
Profile data is based on a separate run with oprofile running.

async dd
                                    3.15.0-rc3            3.15.0-rc3
                                       vanilla           accessed-v2
ext3    Max      elapsed     13.9900 (  0.00%)     11.5900 ( 17.16%)
tmpfs	Max      elapsed      0.5100 (  0.00%)      0.4900 (  3.92%)
btrfs   Max      elapsed     12.8100 (  0.00%)     12.7800 (  0.23%)
ext4	Max      elapsed     18.6000 (  0.00%)     13.3400 ( 28.28%)
xfs	Max      elapsed     12.5600 (  0.00%)      2.0900 ( 83.36%)

The XFS figure is a bit strange as it managed to avoid a worst case by
sheer luck but the average figures looked reasonable.

        samples percentage
ext3       86107    0.9783  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
ext3       23833    0.2710  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
ext3        5036    0.0573  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
ext4       64566    0.8961  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
ext4        5322    0.0713  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
ext4        2869    0.0384  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
xfs        62126    1.7675  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
xfs         1904    0.0554  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
xfs          103    0.0030  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
btrfs      10655    0.1338  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
btrfs       2020    0.0273  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
btrfs        587    0.0079  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed
tmpfs      59562    3.2628  vmlinux-3.15.0-rc4-vanilla        mark_page_accessed
tmpfs       1210    0.0696  vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed
tmpfs         94    0.0054  vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed

[akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:10 -07:00

2614 lines
90 KiB
C

/**
* attrib.c - NTFS attribute operations. Part of the Linux-NTFS project.
*
* Copyright (c) 2001-2012 Anton Altaparmakov and Tuxera Inc.
* Copyright (c) 2002 Richard Russon
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the Linux-NTFS
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/buffer_head.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include "attrib.h"
#include "debug.h"
#include "layout.h"
#include "lcnalloc.h"
#include "malloc.h"
#include "mft.h"
#include "ntfs.h"
#include "types.h"
/**
* ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
* @ni: ntfs inode for which to map (part of) a runlist
* @vcn: map runlist part containing this vcn
* @ctx: active attribute search context if present or NULL if not
*
* Map the part of a runlist containing the @vcn of the ntfs inode @ni.
*
* If @ctx is specified, it is an active search context of @ni and its base mft
* record. This is needed when ntfs_map_runlist_nolock() encounters unmapped
* runlist fragments and allows their mapping. If you do not have the mft
* record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock()
* will perform the necessary mapping and unmapping.
*
* Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and
* restores it before returning. Thus, @ctx will be left pointing to the same
* attribute on return as on entry. However, the actual pointers in @ctx may
* point to different memory locations on return, so you must remember to reset
* any cached pointers from the @ctx, i.e. after the call to
* ntfs_map_runlist_nolock(), you will probably want to do:
* m = ctx->mrec;
* a = ctx->attr;
* Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
* you cache ctx->mrec in a variable @m of type MFT_RECORD *.
*
* Return 0 on success and -errno on error. There is one special error code
* which is not an error as such. This is -ENOENT. It means that @vcn is out
* of bounds of the runlist.
*
* Note the runlist can be NULL after this function returns if @vcn is zero and
* the attribute has zero allocated size, i.e. there simply is no runlist.
*
* WARNING: If @ctx is supplied, regardless of whether success or failure is
* returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
* is no longer valid, i.e. you need to either call
* ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
* In that case PTR_ERR(@ctx->mrec) will give you the error code for
* why the mapping of the old inode failed.
*
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist will be modified.
* - If @ctx is NULL, the base mft record of @ni must not be mapped on
* entry and it will be left unmapped on return.
* - If @ctx is not NULL, the base mft record must be mapped on entry
* and it will be left mapped on return.
*/
int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx)
{
VCN end_vcn;
unsigned long flags;
ntfs_inode *base_ni;
MFT_RECORD *m;
ATTR_RECORD *a;
runlist_element *rl;
struct page *put_this_page = NULL;
int err = 0;
bool ctx_is_temporary, ctx_needs_reset;
ntfs_attr_search_ctx old_ctx = { NULL, };
ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
(unsigned long long)vcn);
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
if (!ctx) {
ctx_is_temporary = ctx_needs_reset = true;
m = map_mft_record(base_ni);
if (IS_ERR(m))
return PTR_ERR(m);
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
}
} else {
VCN allocated_size_vcn;
BUG_ON(IS_ERR(ctx->mrec));
a = ctx->attr;
BUG_ON(!a->non_resident);
ctx_is_temporary = false;
end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
read_lock_irqsave(&ni->size_lock, flags);
allocated_size_vcn = ni->allocated_size >>
ni->vol->cluster_size_bits;
read_unlock_irqrestore(&ni->size_lock, flags);
if (!a->data.non_resident.lowest_vcn && end_vcn <= 0)
end_vcn = allocated_size_vcn - 1;
/*
* If we already have the attribute extent containing @vcn in
* @ctx, no need to look it up again. We slightly cheat in
* that if vcn exceeds the allocated size, we will refuse to
* map the runlist below, so there is definitely no need to get
* the right attribute extent.
*/
if (vcn >= allocated_size_vcn || (a->type == ni->type &&
a->name_length == ni->name_len &&
!memcmp((u8*)a + le16_to_cpu(a->name_offset),
ni->name, ni->name_len) &&
sle64_to_cpu(a->data.non_resident.lowest_vcn)
<= vcn && end_vcn >= vcn))
ctx_needs_reset = false;
else {
/* Save the old search context. */
old_ctx = *ctx;
/*
* If the currently mapped (extent) inode is not the
* base inode we will unmap it when we reinitialize the
* search context which means we need to get a
* reference to the page containing the mapped mft
* record so we do not accidentally drop changes to the
* mft record when it has not been marked dirty yet.
*/
if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino !=
old_ctx.base_ntfs_ino) {
put_this_page = old_ctx.ntfs_ino->page;
page_cache_get(put_this_page);
}
/*
* Reinitialize the search context so we can lookup the
* needed attribute extent.
*/
ntfs_attr_reinit_search_ctx(ctx);
ctx_needs_reset = true;
}
}
if (ctx_needs_reset) {
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, vcn, NULL, 0, ctx);
if (unlikely(err)) {
if (err == -ENOENT)
err = -EIO;
goto err_out;
}
BUG_ON(!ctx->attr->non_resident);
}
a = ctx->attr;
/*
* Only decompress the mapping pairs if @vcn is inside it. Otherwise
* we get into problems when we try to map an out of bounds vcn because
* we then try to map the already mapped runlist fragment and
* ntfs_mapping_pairs_decompress() fails.
*/
end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1;
if (unlikely(vcn && vcn >= end_vcn)) {
err = -ENOENT;
goto err_out;
}
rl = ntfs_mapping_pairs_decompress(ni->vol, a, ni->runlist.rl);
if (IS_ERR(rl))
err = PTR_ERR(rl);
else
ni->runlist.rl = rl;
err_out:
if (ctx_is_temporary) {
if (likely(ctx))
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
} else if (ctx_needs_reset) {
/*
* If there is no attribute list, restoring the search context
* is accomplished simply by copying the saved context back over
* the caller supplied context. If there is an attribute list,
* things are more complicated as we need to deal with mapping
* of mft records and resulting potential changes in pointers.
*/
if (NInoAttrList(base_ni)) {
/*
* If the currently mapped (extent) inode is not the
* one we had before, we need to unmap it and map the
* old one.
*/
if (ctx->ntfs_ino != old_ctx.ntfs_ino) {
/*
* If the currently mapped inode is not the
* base inode, unmap it.
*/
if (ctx->base_ntfs_ino && ctx->ntfs_ino !=
ctx->base_ntfs_ino) {
unmap_extent_mft_record(ctx->ntfs_ino);
ctx->mrec = ctx->base_mrec;
BUG_ON(!ctx->mrec);
}
/*
* If the old mapped inode is not the base
* inode, map it.
*/
if (old_ctx.base_ntfs_ino &&
old_ctx.ntfs_ino !=
old_ctx.base_ntfs_ino) {
retry_map:
ctx->mrec = map_mft_record(
old_ctx.ntfs_ino);
/*
* Something bad has happened. If out
* of memory retry till it succeeds.
* Any other errors are fatal and we
* return the error code in ctx->mrec.
* Let the caller deal with it... We
* just need to fudge things so the
* caller can reinit and/or put the
* search context safely.
*/
if (IS_ERR(ctx->mrec)) {
if (PTR_ERR(ctx->mrec) ==
-ENOMEM) {
schedule();
goto retry_map;
} else
old_ctx.ntfs_ino =
old_ctx.
base_ntfs_ino;
}
}
}
/* Update the changed pointers in the saved context. */
if (ctx->mrec != old_ctx.mrec) {
if (!IS_ERR(ctx->mrec))
old_ctx.attr = (ATTR_RECORD*)(
(u8*)ctx->mrec +
((u8*)old_ctx.attr -
(u8*)old_ctx.mrec));
old_ctx.mrec = ctx->mrec;
}
}
/* Restore the search context to the saved one. */
*ctx = old_ctx;
/*
* We drop the reference on the page we took earlier. In the
* case that IS_ERR(ctx->mrec) is true this means we might lose
* some changes to the mft record that had been made between
* the last time it was marked dirty/written out and now. This
* at this stage is not a problem as the mapping error is fatal
* enough that the mft record cannot be written out anyway and
* the caller is very likely to shutdown the whole inode
* immediately and mark the volume dirty for chkdsk to pick up
* the pieces anyway.
*/
if (put_this_page)
page_cache_release(put_this_page);
}
return err;
}
/**
* ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
* @ni: ntfs inode for which to map (part of) a runlist
* @vcn: map runlist part containing this vcn
*
* Map the part of a runlist containing the @vcn of the ntfs inode @ni.
*
* Return 0 on success and -errno on error. There is one special error code
* which is not an error as such. This is -ENOENT. It means that @vcn is out
* of bounds of the runlist.
*
* Locking: - The runlist must be unlocked on entry and is unlocked on return.
* - This function takes the runlist lock for writing and may modify
* the runlist.
*/
int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
{
int err = 0;
down_write(&ni->runlist.lock);
/* Make sure someone else didn't do the work while we were sleeping. */
if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
LCN_RL_NOT_MAPPED))
err = ntfs_map_runlist_nolock(ni, vcn, NULL);
up_write(&ni->runlist.lock);
return err;
}
/**
* ntfs_attr_vcn_to_lcn_nolock - convert a vcn into a lcn given an ntfs inode
* @ni: ntfs inode of the attribute whose runlist to search
* @vcn: vcn to convert
* @write_locked: true if the runlist is locked for writing
*
* Find the virtual cluster number @vcn in the runlist of the ntfs attribute
* described by the ntfs inode @ni and return the corresponding logical cluster
* number (lcn).
*
* If the @vcn is not mapped yet, the attempt is made to map the attribute
* extent containing the @vcn and the vcn to lcn conversion is retried.
*
* If @write_locked is true the caller has locked the runlist for writing and
* if false for reading.
*
* Since lcns must be >= 0, we use negative return codes with special meaning:
*
* Return code Meaning / Description
* ==========================================
* LCN_HOLE Hole / not allocated on disk.
* LCN_ENOENT There is no such vcn in the runlist, i.e. @vcn is out of bounds.
* LCN_ENOMEM Not enough memory to map runlist.
* LCN_EIO Critical error (runlist/file is corrupt, i/o error, etc).
*
* Locking: - The runlist must be locked on entry and is left locked on return.
* - If @write_locked is 'false', i.e. the runlist is locked for reading,
* the lock may be dropped inside the function so you cannot rely on
* the runlist still being the same when this function returns.
*/
LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,
const bool write_locked)
{
LCN lcn;
unsigned long flags;
bool is_retry = false;
BUG_ON(!ni);
ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
ni->mft_no, (unsigned long long)vcn,
write_locked ? "write" : "read");
BUG_ON(!NInoNonResident(ni));
BUG_ON(vcn < 0);
if (!ni->runlist.rl) {
read_lock_irqsave(&ni->size_lock, flags);
if (!ni->allocated_size) {
read_unlock_irqrestore(&ni->size_lock, flags);
return LCN_ENOENT;
}
read_unlock_irqrestore(&ni->size_lock, flags);
}
retry_remap:
/* Convert vcn to lcn. If that fails map the runlist and retry once. */
lcn = ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn);
if (likely(lcn >= LCN_HOLE)) {
ntfs_debug("Done, lcn 0x%llx.", (long long)lcn);
return lcn;
}
if (lcn != LCN_RL_NOT_MAPPED) {
if (lcn != LCN_ENOENT)
lcn = LCN_EIO;
} else if (!is_retry) {
int err;
if (!write_locked) {
up_read(&ni->runlist.lock);
down_write(&ni->runlist.lock);
if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) !=
LCN_RL_NOT_MAPPED)) {
up_write(&ni->runlist.lock);
down_read(&ni->runlist.lock);
goto retry_remap;
}
}
err = ntfs_map_runlist_nolock(ni, vcn, NULL);
if (!write_locked) {
up_write(&ni->runlist.lock);
down_read(&ni->runlist.lock);
}
if (likely(!err)) {
is_retry = true;
goto retry_remap;
}
if (err == -ENOENT)
lcn = LCN_ENOENT;
else if (err == -ENOMEM)
lcn = LCN_ENOMEM;
else
lcn = LCN_EIO;
}
if (lcn != LCN_ENOENT)
ntfs_error(ni->vol->sb, "Failed with error code %lli.",
(long long)lcn);
return lcn;
}
/**
* ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode
* @ni: ntfs inode describing the runlist to search
* @vcn: vcn to find
* @ctx: active attribute search context if present or NULL if not
*
* Find the virtual cluster number @vcn in the runlist described by the ntfs
* inode @ni and return the address of the runlist element containing the @vcn.
*
* If the @vcn is not mapped yet, the attempt is made to map the attribute
* extent containing the @vcn and the vcn to lcn conversion is retried.
*
* If @ctx is specified, it is an active search context of @ni and its base mft
* record. This is needed when ntfs_attr_find_vcn_nolock() encounters unmapped
* runlist fragments and allows their mapping. If you do not have the mft
* record mapped, you can specify @ctx as NULL and ntfs_attr_find_vcn_nolock()
* will perform the necessary mapping and unmapping.
*
* Note, ntfs_attr_find_vcn_nolock() saves the state of @ctx on entry and
* restores it before returning. Thus, @ctx will be left pointing to the same
* attribute on return as on entry. However, the actual pointers in @ctx may
* point to different memory locations on return, so you must remember to reset
* any cached pointers from the @ctx, i.e. after the call to
* ntfs_attr_find_vcn_nolock(), you will probably want to do:
* m = ctx->mrec;
* a = ctx->attr;
* Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
* you cache ctx->mrec in a variable @m of type MFT_RECORD *.
* Note you need to distinguish between the lcn of the returned runlist element
* being >= 0 and LCN_HOLE. In the later case you have to return zeroes on
* read and allocate clusters on write.
*
* Return the runlist element containing the @vcn on success and
* ERR_PTR(-errno) on error. You need to test the return value with IS_ERR()
* to decide if the return is success or failure and PTR_ERR() to get to the
* error code if IS_ERR() is true.
*
* The possible error return codes are:
* -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds.
* -ENOMEM - Not enough memory to map runlist.
* -EIO - Critical error (runlist/file is corrupt, i/o error, etc).
*
* WARNING: If @ctx is supplied, regardless of whether success or failure is
* returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
* is no longer valid, i.e. you need to either call
* ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
* In that case PTR_ERR(@ctx->mrec) will give you the error code for
* why the mapping of the old inode failed.
*
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist may be modified when
* needed runlist fragments need to be mapped.
* - If @ctx is NULL, the base mft record of @ni must not be mapped on
* entry and it will be left unmapped on return.
* - If @ctx is not NULL, the base mft record must be mapped on entry
* and it will be left mapped on return.
*/
runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
ntfs_attr_search_ctx *ctx)
{
unsigned long flags;
runlist_element *rl;
int err = 0;
bool is_retry = false;
BUG_ON(!ni);
ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, with%s ctx.",
ni->mft_no, (unsigned long long)vcn, ctx ? "" : "out");
BUG_ON(!NInoNonResident(ni));
BUG_ON(vcn < 0);
if (!ni->runlist.rl) {
read_lock_irqsave(&ni->size_lock, flags);
if (!ni->allocated_size) {
read_unlock_irqrestore(&ni->size_lock, flags);
return ERR_PTR(-ENOENT);
}
read_unlock_irqrestore(&ni->size_lock, flags);
}
retry_remap:
rl = ni->runlist.rl;
if (likely(rl && vcn >= rl[0].vcn)) {
while (likely(rl->length)) {
if (unlikely(vcn < rl[1].vcn)) {
if (likely(rl->lcn >= LCN_HOLE)) {
ntfs_debug("Done.");
return rl;
}
break;
}
rl++;
}
if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) {
if (likely(rl->lcn == LCN_ENOENT))
err = -ENOENT;
else
err = -EIO;
}
}
if (!err && !is_retry) {
/*
* If the search context is invalid we cannot map the unmapped
* region.
*/
if (IS_ERR(ctx->mrec))
err = PTR_ERR(ctx->mrec);
else {
/*
* The @vcn is in an unmapped region, map the runlist
* and retry.
*/
err = ntfs_map_runlist_nolock(ni, vcn, ctx);
if (likely(!err)) {
is_retry = true;
goto retry_remap;
}
}
if (err == -EINVAL)
err = -EIO;
} else if (!err)
err = -EIO;
if (err != -ENOENT)
ntfs_error(ni->vol->sb, "Failed with error code %i.", err);
return ERR_PTR(err);
}
/**
* ntfs_attr_find - find (next) attribute in mft record
* @type: attribute type to find
* @name: attribute name to find (optional, i.e. NULL means don't care)
* @name_len: attribute name length (only needed if @name present)
* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
* @val: attribute value to find (optional, resident attributes only)
* @val_len: attribute value length
* @ctx: search context with mft record and attribute to search from
*
* You should not need to call this function directly. Use ntfs_attr_lookup()
* instead.
*
* ntfs_attr_find() takes a search context @ctx as parameter and searches the
* mft record specified by @ctx->mrec, beginning at @ctx->attr, for an
* attribute of @type, optionally @name and @val.
*
* If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will
* point to the found attribute.
*
* If the attribute is not found, ntfs_attr_find() returns -ENOENT and
* @ctx->attr will point to the attribute before which the attribute being
* searched for would need to be inserted if such an action were to be desired.
*
* On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is
* undefined and in particular do not rely on it not changing.
*
* If @ctx->is_first is 'true', the search begins with @ctx->attr itself. If it
* is 'false', the search begins after @ctx->attr.
*
* If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and
* @ctx->ntfs_ino must be set to the ntfs inode to which the mft record
* @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at
* the upcase table. If @ic is CASE_SENSITIVE, the comparison is case
* sensitive. When @name is present, @name_len is the @name length in Unicode
* characters.
*
* If @name is not present (NULL), we assume that the unnamed attribute is
* being searched for.
*
* Finally, the resident attribute value @val is looked for, if present. If
* @val is not present (NULL), @val_len is ignored.
*
* ntfs_attr_find() only searches the specified mft record and it ignores the
* presence of an attribute list attribute (unless it is the one being searched
* for, obviously). If you need to take attribute lists into consideration,
* use ntfs_attr_lookup() instead (see below). This also means that you cannot
* use ntfs_attr_find() to search for extent records of non-resident
* attributes, as extents with lowest_vcn != 0 are usually described by the
* attribute list attribute only. - Note that it is possible that the first
* extent is only in the attribute list while the last extent is in the base
* mft record, so do not rely on being able to find the first extent in the
* base mft record.
*
* Warning: Never use @val when looking for attribute types which can be
* non-resident as this most likely will result in a crash!
*/
static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name,
const u32 name_len, const IGNORE_CASE_BOOL ic,
const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
{
ATTR_RECORD *a;
ntfs_volume *vol = ctx->ntfs_ino->vol;
ntfschar *upcase = vol->upcase;
u32 upcase_len = vol->upcase_len;
/*
* Iterate over attributes in mft record starting at @ctx->attr, or the
* attribute following that, if @ctx->is_first is 'true'.
*/
if (ctx->is_first) {
a = ctx->attr;
ctx->is_first = false;
} else
a = (ATTR_RECORD*)((u8*)ctx->attr +
le32_to_cpu(ctx->attr->length));
for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) {
if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
le32_to_cpu(ctx->mrec->bytes_allocated))
break;
ctx->attr = a;
if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) ||
a->type == AT_END))
return -ENOENT;
if (unlikely(!a->length))
break;
if (a->type != type)
continue;
/*
* If @name is present, compare the two names. If @name is
* missing, assume we want an unnamed attribute.
*/
if (!name) {
/* The search failed if the found attribute is named. */
if (a->name_length)
return -ENOENT;
} else if (!ntfs_are_names_equal(name, name_len,
(ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)),
a->name_length, ic, upcase, upcase_len)) {
register int rc;
rc = ntfs_collate_names(name, name_len,
(ntfschar*)((u8*)a +
le16_to_cpu(a->name_offset)),
a->name_length, 1, IGNORE_CASE,
upcase, upcase_len);
/*
* If @name collates before a->name, there is no
* matching attribute.
*/
if (rc == -1)
return -ENOENT;
/* If the strings are not equal, continue search. */
if (rc)
continue;
rc = ntfs_collate_names(name, name_len,
(ntfschar*)((u8*)a +
le16_to_cpu(a->name_offset)),
a->name_length, 1, CASE_SENSITIVE,
upcase, upcase_len);
if (rc == -1)
return -ENOENT;
if (rc)
continue;
}
/*
* The names match or @name not present and attribute is
* unnamed. If no @val specified, we have found the attribute
* and are done.
*/
if (!val)
return 0;
/* @val is present; compare values. */
else {
register int rc;
rc = memcmp(val, (u8*)a + le16_to_cpu(
a->data.resident.value_offset),
min_t(u32, val_len, le32_to_cpu(
a->data.resident.value_length)));
/*
* If @val collates before the current attribute's
* value, there is no matching attribute.
*/
if (!rc) {
register u32 avl;
avl = le32_to_cpu(
a->data.resident.value_length);
if (val_len == avl)
return 0;
if (val_len < avl)
return -ENOENT;
} else if (rc < 0)
return -ENOENT;
}
}
ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk.");
NVolSetErrors(vol);
return -EIO;
}
/**
* load_attribute_list - load an attribute list into memory
* @vol: ntfs volume from which to read
* @runlist: runlist of the attribute list
* @al_start: destination buffer
* @size: size of the destination buffer in bytes
* @initialized_size: initialized size of the attribute list
*
* Walk the runlist @runlist and load all clusters from it copying them into
* the linear buffer @al. The maximum number of bytes copied to @al is @size
* bytes. Note, @size does not need to be a multiple of the cluster size. If
* @initialized_size is less than @size, the region in @al between
* @initialized_size and @size will be zeroed and not read from disk.
*
* Return 0 on success or -errno on error.
*/
int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start,
const s64 size, const s64 initialized_size)
{
LCN lcn;
u8 *al = al_start;
u8 *al_end = al + initialized_size;
runlist_element *rl;
struct buffer_head *bh;
struct super_block *sb;
unsigned long block_size;
unsigned long block, max_block;
int err = 0;
unsigned char block_size_bits;
ntfs_debug("Entering.");
if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 ||
initialized_size > size)
return -EINVAL;
if (!initialized_size) {
memset(al, 0, size);
return 0;
}
sb = vol->sb;
block_size = sb->s_blocksize;
block_size_bits = sb->s_blocksize_bits;
down_read(&runlist->lock);
rl = runlist->rl;
if (!rl) {
ntfs_error(sb, "Cannot read attribute list since runlist is "
"missing.");
goto err_out;
}
/* Read all clusters specified by the runlist one run at a time. */
while (rl->length) {
lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn);
ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.",
(unsigned long long)rl->vcn,
(unsigned long long)lcn);
/* The attribute list cannot be sparse. */
if (lcn < 0) {
ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot "
"read attribute list.");
goto err_out;
}
block = lcn << vol->cluster_size_bits >> block_size_bits;
/* Read the run from device in chunks of block_size bytes. */
max_block = block + (rl->length << vol->cluster_size_bits >>
block_size_bits);
ntfs_debug("max_block = 0x%lx.", max_block);
do {
ntfs_debug("Reading block = 0x%lx.", block);
bh = sb_bread(sb, block);
if (!bh) {
ntfs_error(sb, "sb_bread() failed. Cannot "
"read attribute list.");
goto err_out;
}
if (al + block_size >= al_end)
goto do_final;
memcpy(al, bh->b_data, block_size);
brelse(bh);
al += block_size;
} while (++block < max_block);
rl++;
}
if (initialized_size < size) {
initialize:
memset(al_start + initialized_size, 0, size - initialized_size);
}
done:
up_read(&runlist->lock);
return err;
do_final:
if (al < al_end) {
/*
* Partial block.
*
* Note: The attribute list can be smaller than its allocation
* by multiple clusters. This has been encountered by at least
* two people running Windows XP, thus we cannot do any
* truncation sanity checking here. (AIA)
*/
memcpy(al, bh->b_data, al_end - al);
brelse(bh);
if (initialized_size < size)
goto initialize;
goto done;
}
brelse(bh);
/* Real overflow! */
ntfs_error(sb, "Attribute list buffer overflow. Read attribute list "
"is truncated.");
err_out:
err = -EIO;
goto done;
}
/**
* ntfs_external_attr_find - find an attribute in the attribute list of an inode
* @type: attribute type to find
* @name: attribute name to find (optional, i.e. NULL means don't care)
* @name_len: attribute name length (only needed if @name present)
* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
* @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
* @val: attribute value to find (optional, resident attributes only)
* @val_len: attribute value length
* @ctx: search context with mft record and attribute to search from
*
* You should not need to call this function directly. Use ntfs_attr_lookup()
* instead.
*
* Find an attribute by searching the attribute list for the corresponding
* attribute list entry. Having found the entry, map the mft record if the
* attribute is in a different mft record/inode, ntfs_attr_find() the attribute
* in there and return it.
*
* On first search @ctx->ntfs_ino must be the base mft record and @ctx must
* have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent
* calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is
* then the base inode).
*
* After finishing with the attribute/mft record you need to call
* ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
* mapped inodes, etc).
*
* If the attribute is found, ntfs_external_attr_find() returns 0 and
* @ctx->attr will point to the found attribute. @ctx->mrec will point to the
* mft record in which @ctx->attr is located and @ctx->al_entry will point to
* the attribute list entry for the attribute.
*
* If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and
* @ctx->attr will point to the attribute in the base mft record before which
* the attribute being searched for would need to be inserted if such an action
* were to be desired. @ctx->mrec will point to the mft record in which
* @ctx->attr is located and @ctx->al_entry will point to the attribute list
* entry of the attribute before which the attribute being searched for would
* need to be inserted if such an action were to be desired.
*
* Thus to insert the not found attribute, one wants to add the attribute to
* @ctx->mrec (the base mft record) and if there is not enough space, the
* attribute should be placed in a newly allocated extent mft record. The
* attribute list entry for the inserted attribute should be inserted in the
* attribute list attribute at @ctx->al_entry.
*
* On actual error, ntfs_external_attr_find() returns -EIO. In this case
* @ctx->attr is undefined and in particular do not rely on it not changing.
*/
static int ntfs_external_attr_find(const ATTR_TYPE type,
const ntfschar *name, const u32 name_len,
const IGNORE_CASE_BOOL ic, const VCN lowest_vcn,
const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx)
{
ntfs_inode *base_ni, *ni;
ntfs_volume *vol;
ATTR_LIST_ENTRY *al_entry, *next_al_entry;
u8 *al_start, *al_end;
ATTR_RECORD *a;
ntfschar *al_name;
u32 al_name_len;
int err = 0;
static const char *es = " Unmount and run chkdsk.";
ni = ctx->ntfs_ino;
base_ni = ctx->base_ntfs_ino;
ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type);
if (!base_ni) {
/* First call happens with the base mft record. */
base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino;
ctx->base_mrec = ctx->mrec;
}
if (ni == base_ni)
ctx->base_attr = ctx->attr;
if (type == AT_END)
goto not_found;
vol = base_ni->vol;
al_start = base_ni->attr_list;
al_end = al_start + base_ni->attr_list_size;
if (!ctx->al_entry)
ctx->al_entry = (ATTR_LIST_ENTRY*)al_start;
/*
* Iterate over entries in attribute list starting at @ctx->al_entry,
* or the entry following that, if @ctx->is_first is 'true'.
*/
if (ctx->is_first) {
al_entry = ctx->al_entry;
ctx->is_first = false;
} else
al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry +
le16_to_cpu(ctx->al_entry->length));
for (;; al_entry = next_al_entry) {
/* Out of bounds check. */
if ((u8*)al_entry < base_ni->attr_list ||
(u8*)al_entry > al_end)
break; /* Inode is corrupt. */
ctx->al_entry = al_entry;
/* Catch the end of the attribute list. */
if ((u8*)al_entry == al_end)
goto not_found;
if (!al_entry->length)
break;
if ((u8*)al_entry + 6 > al_end || (u8*)al_entry +
le16_to_cpu(al_entry->length) > al_end)
break;
next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry +
le16_to_cpu(al_entry->length));
if (le32_to_cpu(al_entry->type) > le32_to_cpu(type))
goto not_found;
if (type != al_entry->type)
continue;
/*
* If @name is present, compare the two names. If @name is
* missing, assume we want an unnamed attribute.
*/
al_name_len = al_entry->name_length;
al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset);
if (!name) {
if (al_name_len)
goto not_found;
} else if (!ntfs_are_names_equal(al_name, al_name_len, name,
name_len, ic, vol->upcase, vol->upcase_len)) {
register int rc;
rc = ntfs_collate_names(name, name_len, al_name,
al_name_len, 1, IGNORE_CASE,
vol->upcase, vol->upcase_len);
/*
* If @name collates before al_name, there is no
* matching attribute.
*/
if (rc == -1)
goto not_found;
/* If the strings are not equal, continue search. */
if (rc)
continue;
/*
* FIXME: Reverse engineering showed 0, IGNORE_CASE but
* that is inconsistent with ntfs_attr_find(). The
* subsequent rc checks were also different. Perhaps I
* made a mistake in one of the two. Need to recheck
* which is correct or at least see what is going on...
* (AIA)
*/
rc = ntfs_collate_names(name, name_len, al_name,
al_name_len, 1, CASE_SENSITIVE,
vol->upcase, vol->upcase_len);
if (rc == -1)
goto not_found;
if (rc)
continue;
}
/*
* The names match or @name not present and attribute is
* unnamed. Now check @lowest_vcn. Continue search if the
* next attribute list entry still fits @lowest_vcn. Otherwise
* we have reached the right one or the search has failed.
*/
if (lowest_vcn && (u8*)next_al_entry >= al_start &&
(u8*)next_al_entry + 6 < al_end &&
(u8*)next_al_entry + le16_to_cpu(
next_al_entry->length) <= al_end &&
sle64_to_cpu(next_al_entry->lowest_vcn) <=
lowest_vcn &&
next_al_entry->type == al_entry->type &&
next_al_entry->name_length == al_name_len &&
ntfs_are_names_equal((ntfschar*)((u8*)
next_al_entry +
next_al_entry->name_offset),
next_al_entry->name_length,
al_name, al_name_len, CASE_SENSITIVE,
vol->upcase, vol->upcase_len))
continue;
if (MREF_LE(al_entry->mft_reference) == ni->mft_no) {
if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) {
ntfs_error(vol->sb, "Found stale mft "
"reference in attribute list "
"of base inode 0x%lx.%s",
base_ni->mft_no, es);
err = -EIO;
break;
}
} else { /* Mft references do not match. */
/* If there is a mapped record unmap it first. */
if (ni != base_ni)
unmap_extent_mft_record(ni);
/* Do we want the base record back? */
if (MREF_LE(al_entry->mft_reference) ==
base_ni->mft_no) {
ni = ctx->ntfs_ino = base_ni;
ctx->mrec = ctx->base_mrec;
} else {
/* We want an extent record. */
ctx->mrec = map_extent_mft_record(base_ni,
le64_to_cpu(
al_entry->mft_reference), &ni);
if (IS_ERR(ctx->mrec)) {
ntfs_error(vol->sb, "Failed to map "
"extent mft record "
"0x%lx of base inode "
"0x%lx.%s",
MREF_LE(al_entry->
mft_reference),
base_ni->mft_no, es);
err = PTR_ERR(ctx->mrec);
if (err == -ENOENT)
err = -EIO;
/* Cause @ctx to be sanitized below. */
ni = NULL;
break;
}
ctx->ntfs_ino = ni;
}
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
le16_to_cpu(ctx->mrec->attrs_offset));
}
/*
* ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the
* mft record containing the attribute represented by the
* current al_entry.
*/
/*
* We could call into ntfs_attr_find() to find the right
* attribute in this mft record but this would be less
* efficient and not quite accurate as ntfs_attr_find() ignores
* the attribute instance numbers for example which become
* important when one plays with attribute lists. Also,
* because a proper match has been found in the attribute list
* entry above, the comparison can now be optimized. So it is
* worth re-implementing a simplified ntfs_attr_find() here.
*/
a = ctx->attr;
/*
* Use a manual loop so we can still use break and continue
* with the same meanings as above.
*/
do_next_attr_loop:
if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec +
le32_to_cpu(ctx->mrec->bytes_allocated))
break;
if (a->type == AT_END)
break;
if (!a->length)
break;
if (al_entry->instance != a->instance)
goto do_next_attr;
/*
* If the type and/or the name are mismatched between the
* attribute list entry and the attribute record, there is
* corruption so we break and return error EIO.
*/
if (al_entry->type != a->type)
break;
if (!ntfs_are_names_equal((ntfschar*)((u8*)a +
le16_to_cpu(a->name_offset)), a->name_length,
al_name, al_name_len, CASE_SENSITIVE,
vol->upcase, vol->upcase_len))
break;
ctx->attr = a;
/*
* If no @val specified or @val specified and it matches, we
* have found it!
*/
if (!val || (!a->non_resident && le32_to_cpu(
a->data.resident.value_length) == val_len &&
!memcmp((u8*)a +
le16_to_cpu(a->data.resident.value_offset),
val, val_len))) {
ntfs_debug("Done, found.");
return 0;
}
do_next_attr:
/* Proceed to the next attribute in the current mft record. */
a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length));
goto do_next_attr_loop;
}
if (!err) {
ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt "
"attribute list attribute.%s", base_ni->mft_no,
es);
err = -EIO;
}
if (ni != base_ni) {
if (ni)
unmap_extent_mft_record(ni);
ctx->ntfs_ino = base_ni;
ctx->mrec = ctx->base_mrec;
ctx->attr = ctx->base_attr;
}
if (err != -ENOMEM)
NVolSetErrors(vol);
return err;
not_found:
/*
* If we were looking for AT_END, we reset the search context @ctx and
* use ntfs_attr_find() to seek to the end of the base mft record.
*/
if (type == AT_END) {
ntfs_attr_reinit_search_ctx(ctx);
return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len,
ctx);
}
/*
* The attribute was not found. Before we return, we want to ensure
* @ctx->mrec and @ctx->attr indicate the position at which the
* attribute should be inserted in the base mft record. Since we also
* want to preserve @ctx->al_entry we cannot reinitialize the search
* context using ntfs_attr_reinit_search_ctx() as this would set
* @ctx->al_entry to NULL. Thus we do the necessary bits manually (see
* ntfs_attr_init_search_ctx() below). Note, we _only_ preserve
* @ctx->al_entry as the remaining fields (base_*) are identical to
* their non base_ counterparts and we cannot set @ctx->base_attr
* correctly yet as we do not know what @ctx->attr will be set to by
* the call to ntfs_attr_find() below.
*/
if (ni != base_ni)
unmap_extent_mft_record(ni);
ctx->mrec = ctx->base_mrec;
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
le16_to_cpu(ctx->mrec->attrs_offset));
ctx->is_first = true;
ctx->ntfs_ino = base_ni;
ctx->base_ntfs_ino = NULL;
ctx->base_mrec = NULL;
ctx->base_attr = NULL;
/*
* In case there are multiple matches in the base mft record, need to
* keep enumerating until we get an attribute not found response (or
* another error), otherwise we would keep returning the same attribute
* over and over again and all programs using us for enumeration would
* lock up in a tight loop.
*/
do {
err = ntfs_attr_find(type, name, name_len, ic, val, val_len,
ctx);
} while (!err);
ntfs_debug("Done, not found.");
return err;
}
/**
* ntfs_attr_lookup - find an attribute in an ntfs inode
* @type: attribute type to find
* @name: attribute name to find (optional, i.e. NULL means don't care)
* @name_len: attribute name length (only needed if @name present)
* @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present)
* @lowest_vcn: lowest vcn to find (optional, non-resident attributes only)
* @val: attribute value to find (optional, resident attributes only)
* @val_len: attribute value length
* @ctx: search context with mft record and attribute to search from
*
* Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must
* be the base mft record and @ctx must have been obtained from a call to
* ntfs_attr_get_search_ctx().
*
* This function transparently handles attribute lists and @ctx is used to
* continue searches where they were left off at.
*
* After finishing with the attribute/mft record you need to call
* ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any
* mapped inodes, etc).
*
* Return 0 if the search was successful and -errno if not.
*
* When 0, @ctx->attr is the found attribute and it is in mft record
* @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is
* the attribute list entry of the found attribute.
*
* When -ENOENT, @ctx->attr is the attribute which collates just after the
* attribute being searched for, i.e. if one wants to add the attribute to the
* mft record this is the correct place to insert it into. If an attribute
* list attribute is present, @ctx->al_entry is the attribute list entry which
* collates just after the attribute list entry of the attribute being searched
* for, i.e. if one wants to add the attribute to the mft record this is the
* correct place to insert its attribute list entry into.
*
* When -errno != -ENOENT, an error occurred during the lookup. @ctx->attr is
* then undefined and in particular you should not rely on it not changing.
*/
int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
const u32 name_len, const IGNORE_CASE_BOOL ic,
const VCN lowest_vcn, const u8 *val, const u32 val_len,
ntfs_attr_search_ctx *ctx)
{
ntfs_inode *base_ni;
ntfs_debug("Entering.");
BUG_ON(IS_ERR(ctx->mrec));
if (ctx->base_ntfs_ino)
base_ni = ctx->base_ntfs_ino;
else
base_ni = ctx->ntfs_ino;
/* Sanity check, just for debugging really. */
BUG_ON(!base_ni);
if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST)
return ntfs_attr_find(type, name, name_len, ic, val, val_len,
ctx);
return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn,
val, val_len, ctx);
}
/**
* ntfs_attr_init_search_ctx - initialize an attribute search context
* @ctx: attribute search context to initialize
* @ni: ntfs inode with which to initialize the search context
* @mrec: mft record with which to initialize the search context
*
* Initialize the attribute search context @ctx with @ni and @mrec.
*/
static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx,
ntfs_inode *ni, MFT_RECORD *mrec)
{
*ctx = (ntfs_attr_search_ctx) {
.mrec = mrec,
/* Sanity checks are performed elsewhere. */
.attr = (ATTR_RECORD*)((u8*)mrec +
le16_to_cpu(mrec->attrs_offset)),
.is_first = true,
.ntfs_ino = ni,
};
}
/**
* ntfs_attr_reinit_search_ctx - reinitialize an attribute search context
* @ctx: attribute search context to reinitialize
*
* Reinitialize the attribute search context @ctx, unmapping an associated
* extent mft record if present, and initialize the search context again.
*
* This is used when a search for a new attribute is being started to reset
* the search context to the beginning.
*/
void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx)
{
if (likely(!ctx->base_ntfs_ino)) {
/* No attribute list. */
ctx->is_first = true;
/* Sanity checks are performed elsewhere. */
ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec +
le16_to_cpu(ctx->mrec->attrs_offset));
/*
* This needs resetting due to ntfs_external_attr_find() which
* can leave it set despite having zeroed ctx->base_ntfs_ino.
*/
ctx->al_entry = NULL;
return;
} /* Attribute list. */
if (ctx->ntfs_ino != ctx->base_ntfs_ino)
unmap_extent_mft_record(ctx->ntfs_ino);
ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec);
return;
}
/**
* ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context
* @ni: ntfs inode with which to initialize the search context
* @mrec: mft record with which to initialize the search context
*
* Allocate a new attribute search context, initialize it with @ni and @mrec,
* and return it. Return NULL if allocation failed.
*/
ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec)
{
ntfs_attr_search_ctx *ctx;
ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, GFP_NOFS);
if (ctx)
ntfs_attr_init_search_ctx(ctx, ni, mrec);
return ctx;
}
/**
* ntfs_attr_put_search_ctx - release an attribute search context
* @ctx: attribute search context to free
*
* Release the attribute search context @ctx, unmapping an associated extent
* mft record if present.
*/
void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx)
{
if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino)
unmap_extent_mft_record(ctx->ntfs_ino);
kmem_cache_free(ntfs_attr_ctx_cache, ctx);
return;
}
#ifdef NTFS_RW
/**
* ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file
* @vol: ntfs volume to which the attribute belongs
* @type: attribute type which to find
*
* Search for the attribute definition record corresponding to the attribute
* @type in the $AttrDef system file.
*
* Return the attribute type definition record if found and NULL if not found.
*/
static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol,
const ATTR_TYPE type)
{
ATTR_DEF *ad;
BUG_ON(!vol->attrdef);
BUG_ON(!type);
for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef <
vol->attrdef_size && ad->type; ++ad) {
/* We have not found it yet, carry on searching. */
if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type)))
continue;
/* We found the attribute; return it. */
if (likely(ad->type == type))
return ad;
/* We have gone too far already. No point in continuing. */
break;
}
/* Attribute not found. */
ntfs_debug("Attribute type 0x%x not found in $AttrDef.",
le32_to_cpu(type));
return NULL;
}
/**
* ntfs_attr_size_bounds_check - check a size of an attribute type for validity
* @vol: ntfs volume to which the attribute belongs
* @type: attribute type which to check
* @size: size which to check
*
* Check whether the @size in bytes is valid for an attribute of @type on the
* ntfs volume @vol. This information is obtained from $AttrDef system file.
*
* Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not
* listed in $AttrDef.
*/
int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type,
const s64 size)
{
ATTR_DEF *ad;
BUG_ON(size < 0);
/*
* $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not
* listed in $AttrDef.
*/
if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024))
return -ERANGE;
/* Get the $AttrDef entry for the attribute @type. */
ad = ntfs_attr_find_in_attrdef(vol, type);
if (unlikely(!ad))
return -ENOENT;
/* Do the bounds check. */
if (((sle64_to_cpu(ad->min_size) > 0) &&
size < sle64_to_cpu(ad->min_size)) ||
((sle64_to_cpu(ad->max_size) > 0) && size >
sle64_to_cpu(ad->max_size)))
return -ERANGE;
return 0;
}
/**
* ntfs_attr_can_be_non_resident - check if an attribute can be non-resident
* @vol: ntfs volume to which the attribute belongs
* @type: attribute type which to check
*
* Check whether the attribute of @type on the ntfs volume @vol is allowed to
* be non-resident. This information is obtained from $AttrDef system file.
*
* Return 0 if the attribute is allowed to be non-resident, -EPERM if not, and
* -ENOENT if the attribute is not listed in $AttrDef.
*/
int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type)
{
ATTR_DEF *ad;
/* Find the attribute definition record in $AttrDef. */
ad = ntfs_attr_find_in_attrdef(vol, type);
if (unlikely(!ad))
return -ENOENT;
/* Check the flags and return the result. */
if (ad->flags & ATTR_DEF_RESIDENT)
return -EPERM;
return 0;
}
/**
* ntfs_attr_can_be_resident - check if an attribute can be resident
* @vol: ntfs volume to which the attribute belongs
* @type: attribute type which to check
*
* Check whether the attribute of @type on the ntfs volume @vol is allowed to
* be resident. This information is derived from our ntfs knowledge and may
* not be completely accurate, especially when user defined attributes are
* present. Basically we allow everything to be resident except for index
* allocation and $EA attributes.
*
* Return 0 if the attribute is allowed to be non-resident and -EPERM if not.
*
* Warning: In the system file $MFT the attribute $Bitmap must be non-resident
* otherwise windows will not boot (blue screen of death)! We cannot
* check for this here as we do not know which inode's $Bitmap is
* being asked about so the caller needs to special case this.
*/
int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type)
{
if (type == AT_INDEX_ALLOCATION)
return -EPERM;
return 0;
}
/**
* ntfs_attr_record_resize - resize an attribute record
* @m: mft record containing attribute record
* @a: attribute record to resize
* @new_size: new size in bytes to which to resize the attribute record @a
*
* Resize the attribute record @a, i.e. the resident part of the attribute, in
* the mft record @m to @new_size bytes.
*
* Return 0 on success and -errno on error. The following error codes are
* defined:
* -ENOSPC - Not enough space in the mft record @m to perform the resize.
*
* Note: On error, no modifications have been performed whatsoever.
*
* Warning: If you make a record smaller without having copied all the data you
* are interested in the data may be overwritten.
*/
int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size)
{
ntfs_debug("Entering for new_size %u.", new_size);
/* Align to 8 bytes if it is not already done. */
if (new_size & 7)
new_size = (new_size + 7) & ~7;
/* If the actual attribute length has changed, move things around. */
if (new_size != le32_to_cpu(a->length)) {
u32 new_muse = le32_to_cpu(m->bytes_in_use) -
le32_to_cpu(a->length) + new_size;
/* Not enough space in this mft record. */
if (new_muse > le32_to_cpu(m->bytes_allocated))
return -ENOSPC;
/* Move attributes following @a to their new location. */
memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length),
le32_to_cpu(m->bytes_in_use) - ((u8*)a -
(u8*)m) - le32_to_cpu(a->length));
/* Adjust @m to reflect the change in used space. */
m->bytes_in_use = cpu_to_le32(new_muse);
/* Adjust @a to reflect the new size. */
if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length))
a->length = cpu_to_le32(new_size);
}
return 0;
}
/**
* ntfs_resident_attr_value_resize - resize the value of a resident attribute
* @m: mft record containing attribute record
* @a: attribute record whose value to resize
* @new_size: new size in bytes to which to resize the attribute value of @a
*
* Resize the value of the attribute @a in the mft record @m to @new_size bytes.
* If the value is made bigger, the newly allocated space is cleared.
*
* Return 0 on success and -errno on error. The following error codes are
* defined:
* -ENOSPC - Not enough space in the mft record @m to perform the resize.
*
* Note: On error, no modifications have been performed whatsoever.
*
* Warning: If you make a record smaller without having copied all the data you
* are interested in the data may be overwritten.
*/
int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
const u32 new_size)
{
u32 old_size;
/* Resize the resident part of the attribute record. */
if (ntfs_attr_record_resize(m, a,
le16_to_cpu(a->data.resident.value_offset) + new_size))
return -ENOSPC;
/*
* The resize succeeded! If we made the attribute value bigger, clear
* the area between the old size and @new_size.
*/
old_size = le32_to_cpu(a->data.resident.value_length);
if (new_size > old_size)
memset((u8*)a + le16_to_cpu(a->data.resident.value_offset) +
old_size, 0, new_size - old_size);
/* Finally update the length of the attribute value. */
a->data.resident.value_length = cpu_to_le32(new_size);
return 0;
}
/**
* ntfs_attr_make_non_resident - convert a resident to a non-resident attribute
* @ni: ntfs inode describing the attribute to convert
* @data_size: size of the resident data to copy to the non-resident attribute
*
* Convert the resident ntfs attribute described by the ntfs inode @ni to a
* non-resident one.
*
* @data_size must be equal to the attribute value size. This is needed since
* we need to know the size before we can map the mft record and our callers
* always know it. The reason we cannot simply read the size from the vfs
* inode i_size is that this is not necessarily uptodate. This happens when
* ntfs_attr_make_non_resident() is called in the ->truncate call path(s).
*
* Return 0 on success and -errno on error. The following error return codes
* are defined:
* -EPERM - The attribute is not allowed to be non-resident.
* -ENOMEM - Not enough memory.
* -ENOSPC - Not enough disk space.
* -EINVAL - Attribute not defined on the volume.
* -EIO - I/o error or other error.
* Note that -ENOSPC is also returned in the case that there is not enough
* space in the mft record to do the conversion. This can happen when the mft
* record is already very full. The caller is responsible for trying to make
* space in the mft record and trying again. FIXME: Do we need a separate
* error return code for this kind of -ENOSPC or is it always worth trying
* again in case the attribute may then fit in a resident state so no need to
* make it non-resident at all? Ho-hum... (AIA)
*
* NOTE to self: No changes in the attribute list are required to move from
* a resident to a non-resident attribute.
*
* Locking: - The caller must hold i_mutex on the inode.
*/
int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size)
{
s64 new_size;
struct inode *vi = VFS_I(ni);
ntfs_volume *vol = ni->vol;
ntfs_inode *base_ni;
MFT_RECORD *m;
ATTR_RECORD *a;
ntfs_attr_search_ctx *ctx;
struct page *page;
runlist_element *rl;
u8 *kaddr;
unsigned long flags;
int mp_size, mp_ofs, name_ofs, arec_size, err, err2;
u32 attr_size;
u8 old_res_attr_flags;
/* Check that the attribute is allowed to be non-resident. */
err = ntfs_attr_can_be_non_resident(vol, ni->type);
if (unlikely(err)) {
if (err == -EPERM)
ntfs_debug("Attribute is not allowed to be "
"non-resident.");
else
ntfs_debug("Attribute not defined on the NTFS "
"volume!");
return err;
}
/*
* FIXME: Compressed and encrypted attributes are not supported when
* writing and we should never have gotten here for them.
*/
BUG_ON(NInoCompressed(ni));
BUG_ON(NInoEncrypted(ni));
/*
* The size needs to be aligned to a cluster boundary for allocation
* purposes.
*/
new_size = (data_size + vol->cluster_size - 1) &
~(vol->cluster_size - 1);
if (new_size > 0) {
/*
* Will need the page later and since the page lock nests
* outside all ntfs locks, we need to get the page now.
*/
page = find_or_create_page(vi->i_mapping, 0,
mapping_gfp_mask(vi->i_mapping));
if (unlikely(!page))
return -ENOMEM;
/* Start by allocating clusters to hold the attribute value. */
rl = ntfs_cluster_alloc(vol, 0, new_size >>
vol->cluster_size_bits, -1, DATA_ZONE, true);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
ntfs_debug("Failed to allocate cluster%s, error code "
"%i.", (new_size >>
vol->cluster_size_bits) > 1 ? "s" : "",
err);
goto page_err_out;
}
} else {
rl = NULL;
page = NULL;
}
/* Determine the size of the mapping pairs array. */
mp_size = ntfs_get_size_for_mapping_pairs(vol, rl, 0, -1);
if (unlikely(mp_size < 0)) {
err = mp_size;
ntfs_debug("Failed to get size for mapping pairs array, error "
"code %i.", err);
goto rl_err_out;
}
down_write(&ni->runlist.lock);
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
m = map_mft_record(base_ni);
if (IS_ERR(m)) {
err = PTR_ERR(m);
m = NULL;
ctx = NULL;
goto err_out;
}
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
}
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, 0, NULL, 0, ctx);
if (unlikely(err)) {
if (err == -ENOENT)
err = -EIO;
goto err_out;
}
m = ctx->mrec;
a = ctx->attr;
BUG_ON(NInoNonResident(ni));
BUG_ON(a->non_resident);
/*
* Calculate new offsets for the name and the mapping pairs array.
*/
if (NInoSparse(ni) || NInoCompressed(ni))
name_ofs = (offsetof(ATTR_REC,
data.non_resident.compressed_size) +
sizeof(a->data.non_resident.compressed_size) +
7) & ~7;
else
name_ofs = (offsetof(ATTR_REC,
data.non_resident.compressed_size) + 7) & ~7;
mp_ofs = (name_ofs + a->name_length * sizeof(ntfschar) + 7) & ~7;
/*
* Determine the size of the resident part of the now non-resident
* attribute record.
*/
arec_size = (mp_ofs + mp_size + 7) & ~7;
/*
* If the page is not uptodate bring it uptodate by copying from the
* attribute value.
*/
attr_size = le32_to_cpu(a->data.resident.value_length);
BUG_ON(attr_size != data_size);
if (page && !PageUptodate(page)) {
kaddr = kmap_atomic(page);
memcpy(kaddr, (u8*)a +
le16_to_cpu(a->data.resident.value_offset),
attr_size);
memset(kaddr + attr_size, 0, PAGE_CACHE_SIZE - attr_size);
kunmap_atomic(kaddr);
flush_dcache_page(page);
SetPageUptodate(page);
}
/* Backup the attribute flag. */
old_res_attr_flags = a->data.resident.flags;
/* Resize the resident part of the attribute record. */
err = ntfs_attr_record_resize(m, a, arec_size);
if (unlikely(err))
goto err_out;
/*
* Convert the resident part of the attribute record to describe a
* non-resident attribute.
*/
a->non_resident = 1;
/* Move the attribute name if it exists and update the offset. */
if (a->name_length)
memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset),
a->name_length * sizeof(ntfschar));
a->name_offset = cpu_to_le16(name_ofs);
/* Setup the fields specific to non-resident attributes. */
a->data.non_resident.lowest_vcn = 0;
a->data.non_resident.highest_vcn = cpu_to_sle64((new_size - 1) >>
vol->cluster_size_bits);
a->data.non_resident.mapping_pairs_offset = cpu_to_le16(mp_ofs);
memset(&a->data.non_resident.reserved, 0,
sizeof(a->data.non_resident.reserved));
a->data.non_resident.allocated_size = cpu_to_sle64(new_size);
a->data.non_resident.data_size =
a->data.non_resident.initialized_size =
cpu_to_sle64(attr_size);
if (NInoSparse(ni) || NInoCompressed(ni)) {
a->data.non_resident.compression_unit = 0;
if (NInoCompressed(ni) || vol->major_ver < 3)
a->data.non_resident.compression_unit = 4;
a->data.non_resident.compressed_size =
a->data.non_resident.allocated_size;
} else
a->data.non_resident.compression_unit = 0;
/* Generate the mapping pairs array into the attribute record. */
err = ntfs_mapping_pairs_build(vol, (u8*)a + mp_ofs,
arec_size - mp_ofs, rl, 0, -1, NULL);
if (unlikely(err)) {
ntfs_debug("Failed to build mapping pairs, error code %i.",
err);
goto undo_err_out;
}
/* Setup the in-memory attribute structure to be non-resident. */
ni->runlist.rl = rl;
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = new_size;
if (NInoSparse(ni) || NInoCompressed(ni)) {
ni->itype.compressed.size = ni->allocated_size;
if (a->data.non_resident.compression_unit) {
ni->itype.compressed.block_size = 1U << (a->data.
non_resident.compression_unit +
vol->cluster_size_bits);
ni->itype.compressed.block_size_bits =
ffs(ni->itype.compressed.block_size) -
1;
ni->itype.compressed.block_clusters = 1U <<
a->data.non_resident.compression_unit;
} else {
ni->itype.compressed.block_size = 0;
ni->itype.compressed.block_size_bits = 0;
ni->itype.compressed.block_clusters = 0;
}
vi->i_blocks = ni->itype.compressed.size >> 9;
} else
vi->i_blocks = ni->allocated_size >> 9;
write_unlock_irqrestore(&ni->size_lock, flags);
/*
* This needs to be last since the address space operations ->readpage
* and ->writepage can run concurrently with us as they are not
* serialized on i_mutex. Note, we are not allowed to fail once we flip
* this switch, which is another reason to do this last.
*/
NInoSetNonResident(ni);
/* Mark the mft record dirty, so it gets written back. */
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
up_write(&ni->runlist.lock);
if (page) {
set_page_dirty(page);
unlock_page(page);
page_cache_release(page);
}
ntfs_debug("Done.");
return 0;
undo_err_out:
/* Convert the attribute back into a resident attribute. */
a->non_resident = 0;
/* Move the attribute name if it exists and update the offset. */
name_ofs = (offsetof(ATTR_RECORD, data.resident.reserved) +
sizeof(a->data.resident.reserved) + 7) & ~7;
if (a->name_length)
memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset),
a->name_length * sizeof(ntfschar));
mp_ofs = (name_ofs + a->name_length * sizeof(ntfschar) + 7) & ~7;
a->name_offset = cpu_to_le16(name_ofs);
arec_size = (mp_ofs + attr_size + 7) & ~7;
/* Resize the resident part of the attribute record. */
err2 = ntfs_attr_record_resize(m, a, arec_size);
if (unlikely(err2)) {
/*
* This cannot happen (well if memory corruption is at work it
* could happen in theory), but deal with it as well as we can.
* If the old size is too small, truncate the attribute,
* otherwise simply give it a larger allocated size.
* FIXME: Should check whether chkdsk complains when the
* allocated size is much bigger than the resident value size.
*/
arec_size = le32_to_cpu(a->length);
if ((mp_ofs + attr_size) > arec_size) {
err2 = attr_size;
attr_size = arec_size - mp_ofs;
ntfs_error(vol->sb, "Failed to undo partial resident "
"to non-resident attribute "
"conversion. Truncating inode 0x%lx, "
"attribute type 0x%x from %i bytes to "
"%i bytes to maintain metadata "
"consistency. THIS MEANS YOU ARE "
"LOSING %i BYTES DATA FROM THIS %s.",
vi->i_ino,
(unsigned)le32_to_cpu(ni->type),
err2, attr_size, err2 - attr_size,
((ni->type == AT_DATA) &&
!ni->name_len) ? "FILE": "ATTRIBUTE");
write_lock_irqsave(&ni->size_lock, flags);
ni->initialized_size = attr_size;
i_size_write(vi, attr_size);
write_unlock_irqrestore(&ni->size_lock, flags);
}
}
/* Setup the fields specific to resident attributes. */
a->data.resident.value_length = cpu_to_le32(attr_size);
a->data.resident.value_offset = cpu_to_le16(mp_ofs);
a->data.resident.flags = old_res_attr_flags;
memset(&a->data.resident.reserved, 0,
sizeof(a->data.resident.reserved));
/* Copy the data from the page back to the attribute value. */
if (page) {
kaddr = kmap_atomic(page);
memcpy((u8*)a + mp_ofs, kaddr, attr_size);
kunmap_atomic(kaddr);
}
/* Setup the allocated size in the ntfs inode in case it changed. */
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = arec_size - mp_ofs;
write_unlock_irqrestore(&ni->size_lock, flags);
/* Mark the mft record dirty, so it gets written back. */
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
err_out:
if (ctx)
ntfs_attr_put_search_ctx(ctx);
if (m)
unmap_mft_record(base_ni);
ni->runlist.rl = NULL;
up_write(&ni->runlist.lock);
rl_err_out:
if (rl) {
if (ntfs_cluster_free_from_rl(vol, rl) < 0) {
ntfs_error(vol->sb, "Failed to release allocated "
"cluster(s) in error code path. Run "
"chkdsk to recover the lost "
"cluster(s).");
NVolSetErrors(vol);
}
ntfs_free(rl);
page_err_out:
unlock_page(page);
page_cache_release(page);
}
if (err == -EINVAL)
err = -EIO;
return err;
}
/**
* ntfs_attr_extend_allocation - extend the allocated space of an attribute
* @ni: ntfs inode of the attribute whose allocation to extend
* @new_alloc_size: new size in bytes to which to extend the allocation to
* @new_data_size: new size in bytes to which to extend the data to
* @data_start: beginning of region which is required to be non-sparse
*
* Extend the allocated space of an attribute described by the ntfs inode @ni
* to @new_alloc_size bytes. If @data_start is -1, the whole extension may be
* implemented as a hole in the file (as long as both the volume and the ntfs
* inode @ni have sparse support enabled). If @data_start is >= 0, then the
* region between the old allocated size and @data_start - 1 may be made sparse
* but the regions between @data_start and @new_alloc_size must be backed by
* actual clusters.
*
* If @new_data_size is -1, it is ignored. If it is >= 0, then the data size
* of the attribute is extended to @new_data_size. Note that the i_size of the
* vfs inode is not updated. Only the data size in the base attribute record
* is updated. The caller has to update i_size separately if this is required.
* WARNING: It is a BUG() for @new_data_size to be smaller than the old data
* size as well as for @new_data_size to be greater than @new_alloc_size.
*
* For resident attributes this involves resizing the attribute record and if
* necessary moving it and/or other attributes into extent mft records and/or
* converting the attribute to a non-resident attribute which in turn involves
* extending the allocation of a non-resident attribute as described below.
*
* For non-resident attributes this involves allocating clusters in the data
* zone on the volume (except for regions that are being made sparse) and
* extending the run list to describe the allocated clusters as well as
* updating the mapping pairs array of the attribute. This in turn involves
* resizing the attribute record and if necessary moving it and/or other
* attributes into extent mft records and/or splitting the attribute record
* into multiple extent attribute records.
*
* Also, the attribute list attribute is updated if present and in some of the
* above cases (the ones where extent mft records/attributes come into play),
* an attribute list attribute is created if not already present.
*
* Return the new allocated size on success and -errno on error. In the case
* that an error is encountered but a partial extension at least up to
* @data_start (if present) is possible, the allocation is partially extended
* and this is returned. This means the caller must check the returned size to
* determine if the extension was partial. If @data_start is -1 then partial
* allocations are not performed.
*
* WARNING: Do not call ntfs_attr_extend_allocation() for $MFT/$DATA.
*
* Locking: This function takes the runlist lock of @ni for writing as well as
* locking the mft record of the base ntfs inode. These locks are maintained
* throughout execution of the function. These locks are required so that the
* attribute can be resized safely and so that it can for example be converted
* from resident to non-resident safely.
*
* TODO: At present attribute list attribute handling is not implemented.
*
* TODO: At present it is not safe to call this function for anything other
* than the $DATA attribute(s) of an uncompressed and unencrypted file.
*/
s64 ntfs_attr_extend_allocation(ntfs_inode *ni, s64 new_alloc_size,
const s64 new_data_size, const s64 data_start)
{
VCN vcn;
s64 ll, allocated_size, start = data_start;
struct inode *vi = VFS_I(ni);
ntfs_volume *vol = ni->vol;
ntfs_inode *base_ni;
MFT_RECORD *m;
ATTR_RECORD *a;
ntfs_attr_search_ctx *ctx;
runlist_element *rl, *rl2;
unsigned long flags;
int err, mp_size;
u32 attr_len = 0; /* Silence stupid gcc warning. */
bool mp_rebuilt;
#ifdef DEBUG
read_lock_irqsave(&ni->size_lock, flags);
allocated_size = ni->allocated_size;
read_unlock_irqrestore(&ni->size_lock, flags);
ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
"old_allocated_size 0x%llx, "
"new_allocated_size 0x%llx, new_data_size 0x%llx, "
"data_start 0x%llx.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type),
(unsigned long long)allocated_size,
(unsigned long long)new_alloc_size,
(unsigned long long)new_data_size,
(unsigned long long)start);
#endif
retry_extend:
/*
* For non-resident attributes, @start and @new_size need to be aligned
* to cluster boundaries for allocation purposes.
*/
if (NInoNonResident(ni)) {
if (start > 0)
start &= ~(s64)vol->cluster_size_mask;
new_alloc_size = (new_alloc_size + vol->cluster_size - 1) &
~(s64)vol->cluster_size_mask;
}
BUG_ON(new_data_size >= 0 && new_data_size > new_alloc_size);
/* Check if new size is allowed in $AttrDef. */
err = ntfs_attr_size_bounds_check(vol, ni->type, new_alloc_size);
if (unlikely(err)) {
/* Only emit errors when the write will fail completely. */
read_lock_irqsave(&ni->size_lock, flags);
allocated_size = ni->allocated_size;
read_unlock_irqrestore(&ni->size_lock, flags);
if (start < 0 || start >= allocated_size) {
if (err == -ERANGE) {
ntfs_error(vol->sb, "Cannot extend allocation "
"of inode 0x%lx, attribute "
"type 0x%x, because the new "
"allocation would exceed the "
"maximum allowed size for "
"this attribute type.",
vi->i_ino, (unsigned)
le32_to_cpu(ni->type));
} else {
ntfs_error(vol->sb, "Cannot extend allocation "
"of inode 0x%lx, attribute "
"type 0x%x, because this "
"attribute type is not "
"defined on the NTFS volume. "
"Possible corruption! You "
"should run chkdsk!",
vi->i_ino, (unsigned)
le32_to_cpu(ni->type));
}
}
/* Translate error code to be POSIX conformant for write(2). */
if (err == -ERANGE)
err = -EFBIG;
else
err = -EIO;
return err;
}
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
/*
* We will be modifying both the runlist (if non-resident) and the mft
* record so lock them both down.
*/
down_write(&ni->runlist.lock);
m = map_mft_record(base_ni);
if (IS_ERR(m)) {
err = PTR_ERR(m);
m = NULL;
ctx = NULL;
goto err_out;
}
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
}
read_lock_irqsave(&ni->size_lock, flags);
allocated_size = ni->allocated_size;
read_unlock_irqrestore(&ni->size_lock, flags);
/*
* If non-resident, seek to the last extent. If resident, there is
* only one extent, so seek to that.
*/
vcn = NInoNonResident(ni) ? allocated_size >> vol->cluster_size_bits :
0;
/*
* Abort if someone did the work whilst we waited for the locks. If we
* just converted the attribute from resident to non-resident it is
* likely that exactly this has happened already. We cannot quite
* abort if we need to update the data size.
*/
if (unlikely(new_alloc_size <= allocated_size)) {
ntfs_debug("Allocated size already exceeds requested size.");
new_alloc_size = allocated_size;
if (new_data_size < 0)
goto done;
/*
* We want the first attribute extent so that we can update the
* data size.
*/
vcn = 0;
}
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, vcn, NULL, 0, ctx);
if (unlikely(err)) {
if (err == -ENOENT)
err = -EIO;
goto err_out;
}
m = ctx->mrec;
a = ctx->attr;
/* Use goto to reduce indentation. */
if (a->non_resident)
goto do_non_resident_extend;
BUG_ON(NInoNonResident(ni));
/* The total length of the attribute value. */
attr_len = le32_to_cpu(a->data.resident.value_length);
/*
* Extend the attribute record to be able to store the new attribute
* size. ntfs_attr_record_resize() will not do anything if the size is
* not changing.
*/
if (new_alloc_size < vol->mft_record_size &&
!ntfs_attr_record_resize(m, a,
le16_to_cpu(a->data.resident.value_offset) +
new_alloc_size)) {
/* The resize succeeded! */
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = le32_to_cpu(a->length) -
le16_to_cpu(a->data.resident.value_offset);
write_unlock_irqrestore(&ni->size_lock, flags);
if (new_data_size >= 0) {
BUG_ON(new_data_size < attr_len);
a->data.resident.value_length =
cpu_to_le32((u32)new_data_size);
}
goto flush_done;
}
/*
* We have to drop all the locks so we can call
* ntfs_attr_make_non_resident(). This could be optimised by try-
* locking the first page cache page and only if that fails dropping
* the locks, locking the page, and redoing all the locking and
* lookups. While this would be a huge optimisation, it is not worth
* it as this is definitely a slow code path.
*/
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
up_write(&ni->runlist.lock);
/*
* Not enough space in the mft record, try to make the attribute
* non-resident and if successful restart the extension process.
*/
err = ntfs_attr_make_non_resident(ni, attr_len);
if (likely(!err))
goto retry_extend;
/*
* Could not make non-resident. If this is due to this not being
* permitted for this attribute type or there not being enough space,
* try to make other attributes non-resident. Otherwise fail.
*/
if (unlikely(err != -EPERM && err != -ENOSPC)) {
/* Only emit errors when the write will fail completely. */
read_lock_irqsave(&ni->size_lock, flags);
allocated_size = ni->allocated_size;
read_unlock_irqrestore(&ni->size_lock, flags);
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation of "
"inode 0x%lx, attribute type 0x%x, "
"because the conversion from resident "
"to non-resident attribute failed "
"with error code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
if (err != -ENOMEM)
err = -EIO;
goto conv_err_out;
}
/* TODO: Not implemented from here, abort. */
read_lock_irqsave(&ni->size_lock, flags);
allocated_size = ni->allocated_size;
read_unlock_irqrestore(&ni->size_lock, flags);
if (start < 0 || start >= allocated_size) {
if (err == -ENOSPC)
ntfs_error(vol->sb, "Not enough space in the mft "
"record/on disk for the non-resident "
"attribute value. This case is not "
"implemented yet.");
else /* if (err == -EPERM) */
ntfs_error(vol->sb, "This attribute type may not be "
"non-resident. This case is not "
"implemented yet.");
}
err = -EOPNOTSUPP;
goto conv_err_out;
#if 0
// TODO: Attempt to make other attributes non-resident.
if (!err)
goto do_resident_extend;
/*
* Both the attribute list attribute and the standard information
* attribute must remain in the base inode. Thus, if this is one of
* these attributes, we have to try to move other attributes out into
* extent mft records instead.
*/
if (ni->type == AT_ATTRIBUTE_LIST ||
ni->type == AT_STANDARD_INFORMATION) {
// TODO: Attempt to move other attributes into extent mft
// records.
err = -EOPNOTSUPP;
if (!err)
goto do_resident_extend;
goto err_out;
}
// TODO: Attempt to move this attribute to an extent mft record, but
// only if it is not already the only attribute in an mft record in
// which case there would be nothing to gain.
err = -EOPNOTSUPP;
if (!err)
goto do_resident_extend;
/* There is nothing we can do to make enough space. )-: */
goto err_out;
#endif
do_non_resident_extend:
BUG_ON(!NInoNonResident(ni));
if (new_alloc_size == allocated_size) {
BUG_ON(vcn);
goto alloc_done;
}
/*
* If the data starts after the end of the old allocation, this is a
* $DATA attribute and sparse attributes are enabled on the volume and
* for this inode, then create a sparse region between the old
* allocated size and the start of the data. Otherwise simply proceed
* with filling the whole space between the old allocated size and the
* new allocated size with clusters.
*/
if ((start >= 0 && start <= allocated_size) || ni->type != AT_DATA ||
!NVolSparseEnabled(vol) || NInoSparseDisabled(ni))
goto skip_sparse;
// TODO: This is not implemented yet. We just fill in with real
// clusters for now...
ntfs_debug("Inserting holes is not-implemented yet. Falling back to "
"allocating real clusters instead.");
skip_sparse:
rl = ni->runlist.rl;
if (likely(rl)) {
/* Seek to the end of the runlist. */
while (rl->length)
rl++;
}
/* If this attribute extent is not mapped, map it now. */
if (unlikely(!rl || rl->lcn == LCN_RL_NOT_MAPPED ||
(rl->lcn == LCN_ENOENT && rl > ni->runlist.rl &&
(rl-1)->lcn == LCN_RL_NOT_MAPPED))) {
if (!rl && !allocated_size)
goto first_alloc;
rl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation "
"of inode 0x%lx, attribute "
"type 0x%x, because the "
"mapping of a runlist "
"fragment failed with error "
"code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type),
err);
if (err != -ENOMEM)
err = -EIO;
goto err_out;
}
ni->runlist.rl = rl;
/* Seek to the end of the runlist. */
while (rl->length)
rl++;
}
/*
* We now know the runlist of the last extent is mapped and @rl is at
* the end of the runlist. We want to begin allocating clusters
* starting at the last allocated cluster to reduce fragmentation. If
* there are no valid LCNs in the attribute we let the cluster
* allocator choose the starting cluster.
*/
/* If the last LCN is a hole or simillar seek back to last real LCN. */
while (rl->lcn < 0 && rl > ni->runlist.rl)
rl--;
first_alloc:
// FIXME: Need to implement partial allocations so at least part of the
// write can be performed when start >= 0. (Needed for POSIX write(2)
// conformance.)
rl2 = ntfs_cluster_alloc(vol, allocated_size >> vol->cluster_size_bits,
(new_alloc_size - allocated_size) >>
vol->cluster_size_bits, (rl && (rl->lcn >= 0)) ?
rl->lcn + rl->length : -1, DATA_ZONE, true);
if (IS_ERR(rl2)) {
err = PTR_ERR(rl2);
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation of "
"inode 0x%lx, attribute type 0x%x, "
"because the allocation of clusters "
"failed with error code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
if (err != -ENOMEM && err != -ENOSPC)
err = -EIO;
goto err_out;
}
rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation of "
"inode 0x%lx, attribute type 0x%x, "
"because the runlist merge failed "
"with error code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
if (err != -ENOMEM)
err = -EIO;
if (ntfs_cluster_free_from_rl(vol, rl2)) {
ntfs_error(vol->sb, "Failed to release allocated "
"cluster(s) in error code path. Run "
"chkdsk to recover the lost "
"cluster(s).");
NVolSetErrors(vol);
}
ntfs_free(rl2);
goto err_out;
}
ni->runlist.rl = rl;
ntfs_debug("Allocated 0x%llx clusters.", (long long)(new_alloc_size -
allocated_size) >> vol->cluster_size_bits);
/* Find the runlist element with which the attribute extent starts. */
ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
rl2 = ntfs_rl_find_vcn_nolock(rl, ll);
BUG_ON(!rl2);
BUG_ON(!rl2->length);
BUG_ON(rl2->lcn < LCN_HOLE);
mp_rebuilt = false;
/* Get the size for the new mapping pairs array for this extent. */
mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
if (unlikely(mp_size <= 0)) {
err = mp_size;
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation of "
"inode 0x%lx, attribute type 0x%x, "
"because determining the size for the "
"mapping pairs failed with error code "
"%i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
err = -EIO;
goto undo_alloc;
}
/* Extend the attribute record to fit the bigger mapping pairs array. */
attr_len = le32_to_cpu(a->length);
err = ntfs_attr_record_resize(m, a, mp_size +
le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
if (unlikely(err)) {
BUG_ON(err != -ENOSPC);
// TODO: Deal with this by moving this extent to a new mft
// record or by starting a new extent in a new mft record,
// possibly by extending this extent partially and filling it
// and creating a new extent for the remainder, or by making
// other attributes non-resident and/or by moving other
// attributes out of this mft record.
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Not enough space in the mft "
"record for the extended attribute "
"record. This case is not "
"implemented yet.");
err = -EOPNOTSUPP;
goto undo_alloc;
}
mp_rebuilt = true;
/* Generate the mapping pairs array directly into the attr record. */
err = ntfs_mapping_pairs_build(vol, (u8*)a +
le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
mp_size, rl2, ll, -1, NULL);
if (unlikely(err)) {
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot extend allocation of "
"inode 0x%lx, attribute type 0x%x, "
"because building the mapping pairs "
"failed with error code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
err = -EIO;
goto undo_alloc;
}
/* Update the highest_vcn. */
a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >>
vol->cluster_size_bits) - 1);
/*
* We now have extended the allocated size of the attribute. Reflect
* this in the ntfs_inode structure and the attribute record.
*/
if (a->data.non_resident.lowest_vcn) {
/*
* We are not in the first attribute extent, switch to it, but
* first ensure the changes will make it to disk later.
*/
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
ntfs_attr_reinit_search_ctx(ctx);
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, 0, NULL, 0, ctx);
if (unlikely(err))
goto restore_undo_alloc;
/* @m is not used any more so no need to set it. */
a = ctx->attr;
}
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = new_alloc_size;
a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size);
/*
* FIXME: This would fail if @ni is a directory, $MFT, or an index,
* since those can have sparse/compressed set. For example can be
* set compressed even though it is not compressed itself and in that
* case the bit means that files are to be created compressed in the
* directory... At present this is ok as this code is only called for
* regular files, and only for their $DATA attribute(s).
* FIXME: The calculation is wrong if we created a hole above. For now
* it does not matter as we never create holes.
*/
if (NInoSparse(ni) || NInoCompressed(ni)) {
ni->itype.compressed.size += new_alloc_size - allocated_size;
a->data.non_resident.compressed_size =
cpu_to_sle64(ni->itype.compressed.size);
vi->i_blocks = ni->itype.compressed.size >> 9;
} else
vi->i_blocks = new_alloc_size >> 9;
write_unlock_irqrestore(&ni->size_lock, flags);
alloc_done:
if (new_data_size >= 0) {
BUG_ON(new_data_size <
sle64_to_cpu(a->data.non_resident.data_size));
a->data.non_resident.data_size = cpu_to_sle64(new_data_size);
}
flush_done:
/* Ensure the changes make it to disk. */
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
done:
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
up_write(&ni->runlist.lock);
ntfs_debug("Done, new_allocated_size 0x%llx.",
(unsigned long long)new_alloc_size);
return new_alloc_size;
restore_undo_alloc:
if (start < 0 || start >= allocated_size)
ntfs_error(vol->sb, "Cannot complete extension of allocation "
"of inode 0x%lx, attribute type 0x%x, because "
"lookup of first attribute extent failed with "
"error code %i.", vi->i_ino,
(unsigned)le32_to_cpu(ni->type), err);
if (err == -ENOENT)
err = -EIO;
ntfs_attr_reinit_search_ctx(ctx);
if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len, CASE_SENSITIVE,
allocated_size >> vol->cluster_size_bits, NULL, 0,
ctx)) {
ntfs_error(vol->sb, "Failed to find last attribute extent of "
"attribute in error code path. Run chkdsk to "
"recover.");
write_lock_irqsave(&ni->size_lock, flags);
ni->allocated_size = new_alloc_size;
/*
* FIXME: This would fail if @ni is a directory... See above.
* FIXME: The calculation is wrong if we created a hole above.
* For now it does not matter as we never create holes.
*/
if (NInoSparse(ni) || NInoCompressed(ni)) {
ni->itype.compressed.size += new_alloc_size -
allocated_size;
vi->i_blocks = ni->itype.compressed.size >> 9;
} else
vi->i_blocks = new_alloc_size >> 9;
write_unlock_irqrestore(&ni->size_lock, flags);
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
up_write(&ni->runlist.lock);
/*
* The only thing that is now wrong is the allocated size of the
* base attribute extent which chkdsk should be able to fix.
*/
NVolSetErrors(vol);
return err;
}
ctx->attr->data.non_resident.highest_vcn = cpu_to_sle64(
(allocated_size >> vol->cluster_size_bits) - 1);
undo_alloc:
ll = allocated_size >> vol->cluster_size_bits;
if (ntfs_cluster_free(ni, ll, -1, ctx) < 0) {
ntfs_error(vol->sb, "Failed to release allocated cluster(s) "
"in error code path. Run chkdsk to recover "
"the lost cluster(s).");
NVolSetErrors(vol);
}
m = ctx->mrec;
a = ctx->attr;
/*
* If the runlist truncation fails and/or the search context is no
* longer valid, we cannot resize the attribute record or build the
* mapping pairs array thus we mark the inode bad so that no access to
* the freed clusters can happen.
*/
if (ntfs_rl_truncate_nolock(vol, &ni->runlist, ll) || IS_ERR(m)) {
ntfs_error(vol->sb, "Failed to %s in error code path. Run "
"chkdsk to recover.", IS_ERR(m) ?
"restore attribute search context" :
"truncate attribute runlist");
NVolSetErrors(vol);
} else if (mp_rebuilt) {
if (ntfs_attr_record_resize(m, a, attr_len)) {
ntfs_error(vol->sb, "Failed to restore attribute "
"record in error code path. Run "
"chkdsk to recover.");
NVolSetErrors(vol);
} else /* if (success) */ {
if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
a->data.non_resident.
mapping_pairs_offset), attr_len -
le16_to_cpu(a->data.non_resident.
mapping_pairs_offset), rl2, ll, -1,
NULL)) {
ntfs_error(vol->sb, "Failed to restore "
"mapping pairs array in error "
"code path. Run chkdsk to "
"recover.");
NVolSetErrors(vol);
}
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
}
}
err_out:
if (ctx)
ntfs_attr_put_search_ctx(ctx);
if (m)
unmap_mft_record(base_ni);
up_write(&ni->runlist.lock);
conv_err_out:
ntfs_debug("Failed. Returning error code %i.", err);
return err;
}
/**
* ntfs_attr_set - fill (a part of) an attribute with a byte
* @ni: ntfs inode describing the attribute to fill
* @ofs: offset inside the attribute at which to start to fill
* @cnt: number of bytes to fill
* @val: the unsigned 8-bit value with which to fill the attribute
*
* Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at
* byte offset @ofs inside the attribute with the constant byte @val.
*
* This function is effectively like memset() applied to an ntfs attribute.
* Note thie function actually only operates on the page cache pages belonging
* to the ntfs attribute and it marks them dirty after doing the memset().
* Thus it relies on the vm dirty page write code paths to cause the modified
* pages to be written to the mft record/disk.
*
* Return 0 on success and -errno on error. An error code of -ESPIPE means
* that @ofs + @cnt were outside the end of the attribute and no write was
* performed.
*/
int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
{
ntfs_volume *vol = ni->vol;
struct address_space *mapping;
struct page *page;
u8 *kaddr;
pgoff_t idx, end;
unsigned start_ofs, end_ofs, size;
ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.",
(long long)ofs, (long long)cnt, val);
BUG_ON(ofs < 0);
BUG_ON(cnt < 0);
if (!cnt)
goto done;
/*
* FIXME: Compressed and encrypted attributes are not supported when
* writing and we should never have gotten here for them.
*/
BUG_ON(NInoCompressed(ni));
BUG_ON(NInoEncrypted(ni));
mapping = VFS_I(ni)->i_mapping;
/* Work out the starting index and page offset. */
idx = ofs >> PAGE_CACHE_SHIFT;
start_ofs = ofs & ~PAGE_CACHE_MASK;
/* Work out the ending index and page offset. */
end = ofs + cnt;
end_ofs = end & ~PAGE_CACHE_MASK;
/* If the end is outside the inode size return -ESPIPE. */
if (unlikely(end > i_size_read(VFS_I(ni)))) {
ntfs_error(vol->sb, "Request exceeds end of attribute.");
return -ESPIPE;
}
end >>= PAGE_CACHE_SHIFT;
/* If there is a first partial page, need to do it the slow way. */
if (start_ofs) {
page = read_mapping_page(mapping, idx, NULL);
if (IS_ERR(page)) {
ntfs_error(vol->sb, "Failed to read first partial "
"page (error, index 0x%lx).", idx);
return PTR_ERR(page);
}
/*
* If the last page is the same as the first page, need to
* limit the write to the end offset.
*/
size = PAGE_CACHE_SIZE;
if (idx == end)
size = end_ofs;
kaddr = kmap_atomic(page);
memset(kaddr + start_ofs, val, size - start_ofs);
flush_dcache_page(page);
kunmap_atomic(kaddr);
set_page_dirty(page);
page_cache_release(page);
balance_dirty_pages_ratelimited(mapping);
cond_resched();
if (idx == end)
goto done;
idx++;
}
/* Do the whole pages the fast way. */
for (; idx < end; idx++) {
/* Find or create the current page. (The page is locked.) */
page = grab_cache_page(mapping, idx);
if (unlikely(!page)) {
ntfs_error(vol->sb, "Insufficient memory to grab "
"page (index 0x%lx).", idx);
return -ENOMEM;
}
kaddr = kmap_atomic(page);
memset(kaddr, val, PAGE_CACHE_SIZE);
flush_dcache_page(page);
kunmap_atomic(kaddr);
/*
* If the page has buffers, mark them uptodate since buffer
* state and not page state is definitive in 2.6 kernels.
*/
if (page_has_buffers(page)) {
struct buffer_head *bh, *head;
bh = head = page_buffers(page);
do {
set_buffer_uptodate(bh);
} while ((bh = bh->b_this_page) != head);
}
/* Now that buffers are uptodate, set the page uptodate, too. */
SetPageUptodate(page);
/*
* Set the page and all its buffers dirty and mark the inode
* dirty, too. The VM will write the page later on.
*/
set_page_dirty(page);
/* Finally unlock and release the page. */
unlock_page(page);
page_cache_release(page);
balance_dirty_pages_ratelimited(mapping);
cond_resched();
}
/* If there is a last partial page, need to do it the slow way. */
if (end_ofs) {
page = read_mapping_page(mapping, idx, NULL);
if (IS_ERR(page)) {
ntfs_error(vol->sb, "Failed to read last partial page "
"(error, index 0x%lx).", idx);
return PTR_ERR(page);
}
kaddr = kmap_atomic(page);
memset(kaddr, val, end_ofs);
flush_dcache_page(page);
kunmap_atomic(kaddr);
set_page_dirty(page);
page_cache_release(page);
balance_dirty_pages_ratelimited(mapping);
cond_resched();
}
done:
ntfs_debug("Done.");
return 0;
}
#endif /* NTFS_RW */