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![]() i_alloc_sem is a rather special rw_semaphore. It's the last one that may be released by a non-owner, and it's write side is always mirrored by real exclusion. It's intended use it to wait for all pending direct I/O requests to finish before starting a truncate. Replace it with a hand-grown construct: - exclusion for truncates is already guaranteed by i_mutex, so it can simply fall way - the reader side is replaced by an i_dio_count member in struct inode that counts the number of pending direct I/O requests. Truncate can't proceed as long as it's non-zero - when i_dio_count reaches non-zero we wake up a pending truncate using wake_up_bit on a new bit in i_flags - new references to i_dio_count can't appear while we are waiting for it to read zero because the direct I/O count always needs i_mutex (or an equivalent like XFS's i_iolock) for starting a new operation. This scheme is much simpler, and saves the space of a spinlock_t and a struct list_head in struct inode (typically 160 bits on a non-debug 64-bit system). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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aops.c | ||
aops.h | ||
attrib.c | ||
attrib.h | ||
bitmap.c | ||
bitmap.h | ||
collate.c | ||
collate.h | ||
compress.c | ||
debug.c | ||
debug.h | ||
dir.c | ||
dir.h | ||
endian.h | ||
file.c | ||
index.c | ||
index.h | ||
inode.c | ||
inode.h | ||
Kconfig | ||
layout.h | ||
lcnalloc.c | ||
lcnalloc.h | ||
logfile.c | ||
logfile.h | ||
Makefile | ||
malloc.h | ||
mft.c | ||
mft.h | ||
mst.c | ||
namei.c | ||
ntfs.h | ||
quota.c | ||
quota.h | ||
runlist.c | ||
runlist.h | ||
super.c | ||
sysctl.c | ||
sysctl.h | ||
time.h | ||
types.h | ||
unistr.c | ||
upcase.c | ||
usnjrnl.c | ||
usnjrnl.h | ||
volume.h |