Qu Wenruo 6ec9765d74 btrfs: introduce compressed_bio::pending_sectors to trace compressed bio ... For btrfs_submit_compressed_read() and btrfs_submit_compressed_write(), we have a pretty weird dance around compressed_bio::pending_bios: btrfs_submit_compressed_read/write() { cb = kmalloc() refcount_set(&cb->pending_bios, 0); bio = btrfs_alloc_bio(); /* NOTE here, we haven't yet submitted any bio */ refcount_set(&cb->pending_bios, 1); for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { if (submit) { /* Here we submit bio, but we always have one * extra pending_bios */ refcount_inc(&cb->pending_bios); ret = btrfs_map_bio(); } } /* Submit the last bio */ ret = btrfs_map_bio(); } There are two reasons why we do this: - compressed_bio::pending_bios is a refcount Thus if it's reduced to 0, it can not be increased again. - To ensure the compressed_bio is not freed by some submitted bios If the submitted bio is finished before the next bio submitted, we can free the compressed_bio completely. But the above code is sometimes confusing, and we can do it better by introducing a new member, compressed_bio::pending_sectors. Now we use compressed_bio::pending_sectors to indicate whether we have any pending sectors under IO or not yet submitted. If pending_sectors == 0, we're definitely the last bio of compressed_bio, and is OK to release the compressed bio. Now the workflow looks like this: btrfs_submit_compressed_read/write() { cb = kmalloc() atomic_set(&cb->pending_bios, 0); refcount_set(&cb->pending_sectors, compressed_len >> sectorsize_bits); bio = btrfs_alloc_bio(); for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { if (submit) { refcount_inc(&cb->pending_bios); ret = btrfs_map_bio(); } } /* Submit the last bio */ refcount_inc(&cb->pending_bios); ret = btrfs_map_bio(); } For now we still need pending_bios for later error handling, but will remove pending_bios eventually after properly handling the errors. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>		2021-10-26 19:08:03 +02:00
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9p
adfs
affs
afs
autofs	autofs: fix wait name hash calculation in autofs_wait()	2021-10-20 21:09:02 -04:00
befs
bfs
btrfs	btrfs: introduce compressed_bio::pending_sectors to trace compressed bio	2021-10-26 19:08:03 +02:00
cachefiles
ceph	ceph: fix handling of "meta" errors	2021-10-19 09:36:06 +02:00
cifs
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fuse	fuse: clean up error exits in fuse_fill_super()	2021-10-21 10:01:39 +02:00
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ksmbd	ksmbd: add buffer validation in session setup	2021-10-20 00:07:10 -05:00
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filesystems.c
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fs_context.c
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fs_types.c
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internal.h
io-wq.c	io-wq: max_worker fixes	2021-10-19 17:09:34 -06:00
io-wq.h
io_uring.c	io_uring: apply worker limits to previous users	2021-10-21 11:19:38 -06:00
ioctl.c
Kconfig
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libfs.c
locks.c
Makefile
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posix_acl.c
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readdir.c
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seq_file.c
signalfd.c
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utimes.c
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