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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Arnd Bergmann](/assets/img/avatar_default.png)
All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
752 lines
16 KiB
C
752 lines
16 KiB
C
/* Daemon interface
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/completion.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/namei.h>
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#include <linux/poll.h>
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#include <linux/mount.h>
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#include <linux/statfs.h>
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#include <linux/ctype.h>
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#include <linux/string.h>
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#include <linux/fs_struct.h>
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#include "internal.h"
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static int cachefiles_daemon_open(struct inode *, struct file *);
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static int cachefiles_daemon_release(struct inode *, struct file *);
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static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
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loff_t *);
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static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
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size_t, loff_t *);
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static unsigned int cachefiles_daemon_poll(struct file *,
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struct poll_table_struct *);
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static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
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static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
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static unsigned long cachefiles_open;
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const struct file_operations cachefiles_daemon_fops = {
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.owner = THIS_MODULE,
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.open = cachefiles_daemon_open,
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.release = cachefiles_daemon_release,
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.read = cachefiles_daemon_read,
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.write = cachefiles_daemon_write,
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.poll = cachefiles_daemon_poll,
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.llseek = noop_llseek,
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};
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struct cachefiles_daemon_cmd {
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char name[8];
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int (*handler)(struct cachefiles_cache *cache, char *args);
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};
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static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
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{ "bind", cachefiles_daemon_bind },
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{ "brun", cachefiles_daemon_brun },
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{ "bcull", cachefiles_daemon_bcull },
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{ "bstop", cachefiles_daemon_bstop },
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{ "cull", cachefiles_daemon_cull },
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{ "debug", cachefiles_daemon_debug },
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{ "dir", cachefiles_daemon_dir },
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{ "frun", cachefiles_daemon_frun },
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{ "fcull", cachefiles_daemon_fcull },
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{ "fstop", cachefiles_daemon_fstop },
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{ "inuse", cachefiles_daemon_inuse },
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{ "secctx", cachefiles_daemon_secctx },
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{ "tag", cachefiles_daemon_tag },
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{ "", NULL }
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};
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/*
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* do various checks
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*/
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static int cachefiles_daemon_open(struct inode *inode, struct file *file)
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{
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struct cachefiles_cache *cache;
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_enter("");
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/* only the superuser may do this */
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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/* the cachefiles device may only be open once at a time */
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if (xchg(&cachefiles_open, 1) == 1)
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return -EBUSY;
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/* allocate a cache record */
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cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
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if (!cache) {
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cachefiles_open = 0;
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return -ENOMEM;
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}
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mutex_init(&cache->daemon_mutex);
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cache->active_nodes = RB_ROOT;
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rwlock_init(&cache->active_lock);
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init_waitqueue_head(&cache->daemon_pollwq);
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/* set default caching limits
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* - limit at 1% free space and/or free files
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* - cull below 5% free space and/or free files
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* - cease culling above 7% free space and/or free files
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*/
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cache->frun_percent = 7;
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cache->fcull_percent = 5;
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cache->fstop_percent = 1;
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cache->brun_percent = 7;
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cache->bcull_percent = 5;
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cache->bstop_percent = 1;
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file->private_data = cache;
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cache->cachefilesd = file;
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return 0;
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}
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/*
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* release a cache
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*/
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static int cachefiles_daemon_release(struct inode *inode, struct file *file)
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{
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struct cachefiles_cache *cache = file->private_data;
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_enter("");
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ASSERT(cache);
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set_bit(CACHEFILES_DEAD, &cache->flags);
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cachefiles_daemon_unbind(cache);
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ASSERT(!cache->active_nodes.rb_node);
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/* clean up the control file interface */
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cache->cachefilesd = NULL;
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file->private_data = NULL;
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cachefiles_open = 0;
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kfree(cache);
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_leave("");
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return 0;
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}
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/*
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* read the cache state
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*/
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static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
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size_t buflen, loff_t *pos)
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{
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struct cachefiles_cache *cache = file->private_data;
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char buffer[256];
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int n;
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//_enter(",,%zu,", buflen);
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if (!test_bit(CACHEFILES_READY, &cache->flags))
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return 0;
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/* check how much space the cache has */
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cachefiles_has_space(cache, 0, 0);
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/* summarise */
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clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
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n = snprintf(buffer, sizeof(buffer),
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"cull=%c"
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" frun=%llx"
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" fcull=%llx"
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" fstop=%llx"
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" brun=%llx"
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" bcull=%llx"
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" bstop=%llx",
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test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
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(unsigned long long) cache->frun,
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(unsigned long long) cache->fcull,
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(unsigned long long) cache->fstop,
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(unsigned long long) cache->brun,
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(unsigned long long) cache->bcull,
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(unsigned long long) cache->bstop
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);
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if (n > buflen)
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return -EMSGSIZE;
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if (copy_to_user(_buffer, buffer, n) != 0)
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return -EFAULT;
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return n;
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}
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/*
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* command the cache
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*/
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static ssize_t cachefiles_daemon_write(struct file *file,
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const char __user *_data,
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size_t datalen,
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loff_t *pos)
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{
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const struct cachefiles_daemon_cmd *cmd;
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struct cachefiles_cache *cache = file->private_data;
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ssize_t ret;
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char *data, *args, *cp;
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//_enter(",,%zu,", datalen);
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ASSERT(cache);
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if (test_bit(CACHEFILES_DEAD, &cache->flags))
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return -EIO;
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if (datalen < 0 || datalen > PAGE_SIZE - 1)
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return -EOPNOTSUPP;
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/* drag the command string into the kernel so we can parse it */
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data = kmalloc(datalen + 1, GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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ret = -EFAULT;
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if (copy_from_user(data, _data, datalen) != 0)
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goto error;
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data[datalen] = '\0';
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ret = -EINVAL;
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if (memchr(data, '\0', datalen))
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goto error;
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/* strip any newline */
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cp = memchr(data, '\n', datalen);
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if (cp) {
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if (cp == data)
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goto error;
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*cp = '\0';
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}
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/* parse the command */
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ret = -EOPNOTSUPP;
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for (args = data; *args; args++)
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if (isspace(*args))
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break;
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if (*args) {
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if (args == data)
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goto error;
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*args = '\0';
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args = skip_spaces(++args);
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}
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/* run the appropriate command handler */
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for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
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if (strcmp(cmd->name, data) == 0)
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goto found_command;
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error:
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kfree(data);
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//_leave(" = %zd", ret);
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return ret;
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found_command:
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mutex_lock(&cache->daemon_mutex);
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ret = -EIO;
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if (!test_bit(CACHEFILES_DEAD, &cache->flags))
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ret = cmd->handler(cache, args);
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mutex_unlock(&cache->daemon_mutex);
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if (ret == 0)
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ret = datalen;
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goto error;
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}
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/*
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* poll for culling state
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* - use POLLOUT to indicate culling state
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*/
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static unsigned int cachefiles_daemon_poll(struct file *file,
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struct poll_table_struct *poll)
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{
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struct cachefiles_cache *cache = file->private_data;
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unsigned int mask;
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poll_wait(file, &cache->daemon_pollwq, poll);
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mask = 0;
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if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
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mask |= POLLIN;
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if (test_bit(CACHEFILES_CULLING, &cache->flags))
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mask |= POLLOUT;
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return mask;
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}
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/*
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* give a range error for cache space constraints
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* - can be tail-called
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*/
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static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
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char *args)
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{
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kerror("Free space limits must be in range"
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" 0%%<=stop<cull<run<100%%");
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return -EINVAL;
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}
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/*
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* set the percentage of files at which to stop culling
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* - command: "frun <N>%"
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*/
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static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
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{
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unsigned long frun;
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_enter(",%s", args);
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if (!*args)
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return -EINVAL;
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frun = simple_strtoul(args, &args, 10);
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if (args[0] != '%' || args[1] != '\0')
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return -EINVAL;
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if (frun <= cache->fcull_percent || frun >= 100)
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return cachefiles_daemon_range_error(cache, args);
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cache->frun_percent = frun;
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return 0;
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}
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/*
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* set the percentage of files at which to start culling
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* - command: "fcull <N>%"
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*/
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static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
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{
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unsigned long fcull;
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_enter(",%s", args);
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if (!*args)
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return -EINVAL;
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fcull = simple_strtoul(args, &args, 10);
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if (args[0] != '%' || args[1] != '\0')
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return -EINVAL;
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if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
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return cachefiles_daemon_range_error(cache, args);
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cache->fcull_percent = fcull;
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return 0;
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}
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/*
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* set the percentage of files at which to stop allocating
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* - command: "fstop <N>%"
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*/
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static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
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{
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unsigned long fstop;
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_enter(",%s", args);
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if (!*args)
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return -EINVAL;
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fstop = simple_strtoul(args, &args, 10);
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if (args[0] != '%' || args[1] != '\0')
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return -EINVAL;
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if (fstop < 0 || fstop >= cache->fcull_percent)
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return cachefiles_daemon_range_error(cache, args);
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cache->fstop_percent = fstop;
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return 0;
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}
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/*
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* set the percentage of blocks at which to stop culling
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* - command: "brun <N>%"
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*/
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static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
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{
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unsigned long brun;
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_enter(",%s", args);
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if (!*args)
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return -EINVAL;
|
|
|
|
brun = simple_strtoul(args, &args, 10);
|
|
if (args[0] != '%' || args[1] != '\0')
|
|
return -EINVAL;
|
|
|
|
if (brun <= cache->bcull_percent || brun >= 100)
|
|
return cachefiles_daemon_range_error(cache, args);
|
|
|
|
cache->brun_percent = brun;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* set the percentage of blocks at which to start culling
|
|
* - command: "bcull <N>%"
|
|
*/
|
|
static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
unsigned long bcull;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (!*args)
|
|
return -EINVAL;
|
|
|
|
bcull = simple_strtoul(args, &args, 10);
|
|
if (args[0] != '%' || args[1] != '\0')
|
|
return -EINVAL;
|
|
|
|
if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
|
|
return cachefiles_daemon_range_error(cache, args);
|
|
|
|
cache->bcull_percent = bcull;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* set the percentage of blocks at which to stop allocating
|
|
* - command: "bstop <N>%"
|
|
*/
|
|
static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
unsigned long bstop;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (!*args)
|
|
return -EINVAL;
|
|
|
|
bstop = simple_strtoul(args, &args, 10);
|
|
if (args[0] != '%' || args[1] != '\0')
|
|
return -EINVAL;
|
|
|
|
if (bstop < 0 || bstop >= cache->bcull_percent)
|
|
return cachefiles_daemon_range_error(cache, args);
|
|
|
|
cache->bstop_percent = bstop;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* set the cache directory
|
|
* - command: "dir <name>"
|
|
*/
|
|
static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
char *dir;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (!*args) {
|
|
kerror("Empty directory specified");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (cache->rootdirname) {
|
|
kerror("Second cache directory specified");
|
|
return -EEXIST;
|
|
}
|
|
|
|
dir = kstrdup(args, GFP_KERNEL);
|
|
if (!dir)
|
|
return -ENOMEM;
|
|
|
|
cache->rootdirname = dir;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* set the cache security context
|
|
* - command: "secctx <ctx>"
|
|
*/
|
|
static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
char *secctx;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (!*args) {
|
|
kerror("Empty security context specified");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (cache->secctx) {
|
|
kerror("Second security context specified");
|
|
return -EINVAL;
|
|
}
|
|
|
|
secctx = kstrdup(args, GFP_KERNEL);
|
|
if (!secctx)
|
|
return -ENOMEM;
|
|
|
|
cache->secctx = secctx;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* set the cache tag
|
|
* - command: "tag <name>"
|
|
*/
|
|
static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
char *tag;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (!*args) {
|
|
kerror("Empty tag specified");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (cache->tag)
|
|
return -EEXIST;
|
|
|
|
tag = kstrdup(args, GFP_KERNEL);
|
|
if (!tag)
|
|
return -ENOMEM;
|
|
|
|
cache->tag = tag;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* request a node in the cache be culled from the current working directory
|
|
* - command: "cull <name>"
|
|
*/
|
|
static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
struct path path;
|
|
const struct cred *saved_cred;
|
|
int ret;
|
|
|
|
_enter(",%s", args);
|
|
|
|
if (strchr(args, '/'))
|
|
goto inval;
|
|
|
|
if (!test_bit(CACHEFILES_READY, &cache->flags)) {
|
|
kerror("cull applied to unready cache");
|
|
return -EIO;
|
|
}
|
|
|
|
if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
|
|
kerror("cull applied to dead cache");
|
|
return -EIO;
|
|
}
|
|
|
|
/* extract the directory dentry from the cwd */
|
|
get_fs_pwd(current->fs, &path);
|
|
|
|
if (!S_ISDIR(path.dentry->d_inode->i_mode))
|
|
goto notdir;
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
ret = cachefiles_cull(cache, path.dentry, args);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
path_put(&path);
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
notdir:
|
|
path_put(&path);
|
|
kerror("cull command requires dirfd to be a directory");
|
|
return -ENOTDIR;
|
|
|
|
inval:
|
|
kerror("cull command requires dirfd and filename");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* set debugging mode
|
|
* - command: "debug <mask>"
|
|
*/
|
|
static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
unsigned long mask;
|
|
|
|
_enter(",%s", args);
|
|
|
|
mask = simple_strtoul(args, &args, 0);
|
|
if (args[0] != '\0')
|
|
goto inval;
|
|
|
|
cachefiles_debug = mask;
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
inval:
|
|
kerror("debug command requires mask");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* find out whether an object in the current working directory is in use or not
|
|
* - command: "inuse <name>"
|
|
*/
|
|
static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
|
|
{
|
|
struct path path;
|
|
const struct cred *saved_cred;
|
|
int ret;
|
|
|
|
//_enter(",%s", args);
|
|
|
|
if (strchr(args, '/'))
|
|
goto inval;
|
|
|
|
if (!test_bit(CACHEFILES_READY, &cache->flags)) {
|
|
kerror("inuse applied to unready cache");
|
|
return -EIO;
|
|
}
|
|
|
|
if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
|
|
kerror("inuse applied to dead cache");
|
|
return -EIO;
|
|
}
|
|
|
|
/* extract the directory dentry from the cwd */
|
|
get_fs_pwd(current->fs, &path);
|
|
|
|
if (!S_ISDIR(path.dentry->d_inode->i_mode))
|
|
goto notdir;
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
ret = cachefiles_check_in_use(cache, path.dentry, args);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
path_put(&path);
|
|
//_leave(" = %d", ret);
|
|
return ret;
|
|
|
|
notdir:
|
|
path_put(&path);
|
|
kerror("inuse command requires dirfd to be a directory");
|
|
return -ENOTDIR;
|
|
|
|
inval:
|
|
kerror("inuse command requires dirfd and filename");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* see if we have space for a number of pages and/or a number of files in the
|
|
* cache
|
|
*/
|
|
int cachefiles_has_space(struct cachefiles_cache *cache,
|
|
unsigned fnr, unsigned bnr)
|
|
{
|
|
struct kstatfs stats;
|
|
struct path path = {
|
|
.mnt = cache->mnt,
|
|
.dentry = cache->mnt->mnt_root,
|
|
};
|
|
int ret;
|
|
|
|
//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
|
|
// (unsigned long long) cache->frun,
|
|
// (unsigned long long) cache->fcull,
|
|
// (unsigned long long) cache->fstop,
|
|
// (unsigned long long) cache->brun,
|
|
// (unsigned long long) cache->bcull,
|
|
// (unsigned long long) cache->bstop,
|
|
// fnr, bnr);
|
|
|
|
/* find out how many pages of blockdev are available */
|
|
memset(&stats, 0, sizeof(stats));
|
|
|
|
ret = vfs_statfs(&path, &stats);
|
|
if (ret < 0) {
|
|
if (ret == -EIO)
|
|
cachefiles_io_error(cache, "statfs failed");
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
stats.f_bavail >>= cache->bshift;
|
|
|
|
//_debug("avail %llu,%llu",
|
|
// (unsigned long long) stats.f_ffree,
|
|
// (unsigned long long) stats.f_bavail);
|
|
|
|
/* see if there is sufficient space */
|
|
if (stats.f_ffree > fnr)
|
|
stats.f_ffree -= fnr;
|
|
else
|
|
stats.f_ffree = 0;
|
|
|
|
if (stats.f_bavail > bnr)
|
|
stats.f_bavail -= bnr;
|
|
else
|
|
stats.f_bavail = 0;
|
|
|
|
ret = -ENOBUFS;
|
|
if (stats.f_ffree < cache->fstop ||
|
|
stats.f_bavail < cache->bstop)
|
|
goto begin_cull;
|
|
|
|
ret = 0;
|
|
if (stats.f_ffree < cache->fcull ||
|
|
stats.f_bavail < cache->bcull)
|
|
goto begin_cull;
|
|
|
|
if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
|
|
stats.f_ffree >= cache->frun &&
|
|
stats.f_bavail >= cache->brun &&
|
|
test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
|
|
) {
|
|
_debug("cease culling");
|
|
cachefiles_state_changed(cache);
|
|
}
|
|
|
|
//_leave(" = 0");
|
|
return 0;
|
|
|
|
begin_cull:
|
|
if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
|
|
_debug("### CULL CACHE ###");
|
|
cachefiles_state_changed(cache);
|
|
}
|
|
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|