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e3b49ea368
Encrypted pages during GC are read and cached in META_MAPPING.
However, due to cached pages in META_MAPPING, there is an issue where
newly written pages are lost by IPU or DIO writes.
Thread A - f2fs_gc() Thread B
/* phase 3 */
down_write(i_gc_rwsem)
ra_data_block() ---- (a)
up_write(i_gc_rwsem)
f2fs_direct_IO() :
- down_read(i_gc_rwsem)
- __blockdev_direct_io()
- get_data_block_dio_write()
- f2fs_dio_submit_bio() ---- (b)
- up_read(i_gc_rwsem)
/* phase 4 */
down_write(i_gc_rwsem)
move_data_block() ---- (c)
up_write(i_gc_rwsem)
(a) In phase 3 of f2fs_gc(), up-to-date page is read from storage and
cached in META_MAPPING.
(b) In thread B, writing new data by IPU or DIO write on same blkaddr as
read in (a). cached page in META_MAPPING become out-dated.
(c) In phase 4 of f2fs_gc(), out-dated page in META_MAPPING is copied to
new blkaddr. In conclusion, the newly written data in (b) is lost.
To address this issue, invalidating pages in META_MAPPING before IPU or
DIO write.
Fixes:
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|---|---|---|
| .. | ||
| acl.c | ||
| acl.h | ||
| checkpoint.c | ||
| compress.c | ||
| data.c | ||
| debug.c | ||
| dir.c | ||
| extent_cache.c | ||
| f2fs.h | ||
| file.c | ||
| gc.c | ||
| gc.h | ||
| hash.c | ||
| inline.c | ||
| inode.c | ||
| iostat.c | ||
| iostat.h | ||
| Kconfig | ||
| Makefile | ||
| namei.c | ||
| node.c | ||
| node.h | ||
| recovery.c | ||
| segment.c | ||
| segment.h | ||
| shrinker.c | ||
| super.c | ||
| sysfs.c | ||
| verity.c | ||
| xattr.c | ||
| xattr.h | ||