| Message ID | 20171219100247.13880-3-nefelim4ag@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
вт, 19 дек. 2017 г. в 13:02, Timofey Titovets <nefelim4ag@gmail.com>: > Both, defrag ioctl and autodefrag - call btrfs_defrag_file() > for file defragmentation. > Kernel default target extent size - 256KiB. > Btrfs progs default - 32MiB. > Both bigger then maximum size of compressed extent - 128KiB. > That lead to rewrite all compressed data on disk. > Fix that by check compression extents with different logic. > As addition, make should_defrag_range() understood compressed extent type, > if requested target compression are same as current extent compression type. > Just don't recompress/rewrite extents. > To avoid useless recompression of compressed extents. > Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com> > --- > fs/btrfs/ioctl.c | 28 +++++++++++++++++++++++++--- > 1 file changed, 25 insertions(+), 3 deletions(-) > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index 45a47d0891fc..b29ea1f0f621 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -1008,7 +1008,7 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em) > static int should_defrag_range(struct inode *inode, u64 start, u32 thresh, > u64 *last_len, u64 *skip, u64 *defrag_end, > - int compress) > + int compress, int compress_type) > { > struct extent_map *em; > int ret = 1; > @@ -1043,8 +1043,29 @@ static int should_defrag_range(struct inode *inode, u64 start, u32 thresh, > * real extent, don't bother defragging it > */ > if (!compress && (*last_len == 0 || *last_len >= thresh) && > - (em->len >= thresh || (!next_mergeable && !prev_mergeable))) > + (em->len >= thresh || (!next_mergeable && !prev_mergeable))) { > ret = 0; > + goto out; > + } > + > + > + /* > + * Try not recompress compressed extents > + * thresh >= BTRFS_MAX_UNCOMPRESSED will lead to > + * recompress all compressed extents > + */ > + if (em->compress_type != 0 && thresh >= BTRFS_MAX_UNCOMPRESSED) { > + if (!compress) { > + if (em->len == BTRFS_MAX_UNCOMPRESSED) > + ret = 0; > + } else { > + if (em->compress_type != compress_type) > + goto out; > + if (em->len == BTRFS_MAX_UNCOMPRESSED) > + ret = 0; > + } > + } > + > out: > /* > * last_len ends up being a counter of how many bytes we've defragged. > @@ -1342,7 +1363,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file, > if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT, > extent_thresh, &last_len, &skip, > - &defrag_end, do_compress)){ > + &defrag_end, do_compress, > + compress_type)){ > unsigned long next; > /* > * the should_defrag function tells us how much to skip > -- > 2.15.1 May be, then, if we don't want add some duck tape for compressed extents and defrag, we can just change default kernel target extent size 256KiB -> 128KiB? That will also fix the issue with autodefrag and compression enabled. Thanks.
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 45a47d0891fc..b29ea1f0f621 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1008,7 +1008,7 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em) static int should_defrag_range(struct inode *inode, u64 start, u32 thresh, u64 *last_len, u64 *skip, u64 *defrag_end, - int compress) + int compress, int compress_type) { struct extent_map *em; int ret = 1; @@ -1043,8 +1043,29 @@ static int should_defrag_range(struct inode *inode, u64 start, u32 thresh, * real extent, don't bother defragging it */ if (!compress && (*last_len == 0 || *last_len >= thresh) && - (em->len >= thresh || (!next_mergeable && !prev_mergeable))) + (em->len >= thresh || (!next_mergeable && !prev_mergeable))) { ret = 0; + goto out; + } + + + /* + * Try not recompress compressed extents + * thresh >= BTRFS_MAX_UNCOMPRESSED will lead to + * recompress all compressed extents + */ + if (em->compress_type != 0 && thresh >= BTRFS_MAX_UNCOMPRESSED) { + if (!compress) { + if (em->len == BTRFS_MAX_UNCOMPRESSED) + ret = 0; + } else { + if (em->compress_type != compress_type) + goto out; + if (em->len == BTRFS_MAX_UNCOMPRESSED) + ret = 0; + } + } + out: /* * last_len ends up being a counter of how many bytes we've defragged. @@ -1342,7 +1363,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file, if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT, extent_thresh, &last_len, &skip, - &defrag_end, do_compress)){ + &defrag_end, do_compress, + compress_type)){ unsigned long next; /* * the should_defrag function tells us how much to skip
Both, defrag ioctl and autodefrag - call btrfs_defrag_file() for file defragmentation. Kernel default target extent size - 256KiB. Btrfs progs default - 32MiB. Both bigger then maximum size of compressed extent - 128KiB. That lead to rewrite all compressed data on disk. Fix that by check compression extents with different logic. As addition, make should_defrag_range() understood compressed extent type, if requested target compression are same as current extent compression type. Just don't recompress/rewrite extents. To avoid useless recompression of compressed extents. Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com> --- fs/btrfs/ioctl.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-)