From: Liu Bo Date: Sat, 28 Jul 2012 21:29:13 +0000 (-0400) Subject: filefrag: fix report of number of extents X-Git-Tag: android-x86-6.0-r1~26^2~343 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=036fda6d487737eac9be086d999b7480a81d37ea;p=android-x86%2Fexternal-e2fsprogs.git filefrag: fix report of number of extents filefrag has several bugs: 1. $ touch f1 $ filefrag f1 f1: 1 extent found ----> bug! $ filefrag -v f1 Filesystem type is: ef53 File size of f1 is 0 (0 blocks, blocksize 4096) f1: 0 extents found 2. $ truncate -s 1m f2 $ filefrag f2 f2: 1 extent found ----> bug! $ filefrag -v f2 Filesystem type is: ef53 File size of f2 is 1048576 (256 blocks, blocksize 4096) f2: 0 extents found 3. $ for i in `seq 11 -2 0`; do dd if=/dev/zero of=f4 bs=4k count=1 seek=$i conv=notrunc oflag=sync &>/dev/null; done $ ll f4 -rw-r--r-- 1 root root 49152 Jun 9 15:09 f4 $ filefrag f4 f4: 7 extents found $ filefrag -v f4 Filesystem type is: ef53 File size of f4 is 49152 (12 blocks, blocksize 4096) ext logical physical expected length flags 0 1 1109993 1 1 3 1109992 1109994 1 2 5 1109991 1109993 1 3 7 1109990 1109992 1 4 9 1109989 1109991 1 5 11 1108207 1109990 1 eof f4: 7 extents found -----------------------> but we only have 6 extents, bug! All of these bugs come from the fact that we've made a mistake on calculating total extents: o we set 1 as default for 'total extents', and this will report 1 extent found even when we don't get any extent from fiemap. o if our first extent does not start from 0(logical addr), total extents will be one more than what it should be. Addresses-Red-Hat-Bugzilla: #840848 Reviewed-by: Eric Sandeen Signed-off-by: Liu Bo Signed-off-by: Theodore Ts'o --- diff --git a/misc/filefrag.c b/misc/filefrag.c index 0583e916..af008fbc 100644 --- a/misc/filefrag.c +++ b/misc/filefrag.c @@ -175,7 +175,7 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents) unsigned int i; static int fiemap_incompat_printed; int fiemap_header_printed = 0; - int tot_extents = 1, n = 0; + int tot_extents = 0, n = 0; int last = 0; int rc; @@ -201,25 +201,17 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents) return rc; } + /* If 0 extents are returned, then more ioctls are not needed */ + if (fiemap->fm_mapped_extents == 0) + break; + if (verbose && !fiemap_header_printed) { - /* - * No extents on first call? - * Skip header and show 0 extents. - */ - if (fiemap->fm_mapped_extents == 0) { - *num_extents = 0; - goto out; - } printf(" ext %*s %*s %*s length flags\n", logical_width, "logical", physical_width, "physical", physical_width, "expected"); fiemap_header_printed = 1; } - /* If 0 extents are returned, then more ioctls are not needed */ - if (fiemap->fm_mapped_extents == 0) - break; - for (i = 0; i < fiemap->fm_mapped_extents; i++) { __u64 phy_blk, logical_blk; unsigned long ext_len; @@ -228,10 +220,13 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents) ext_len = fm_ext[i].fe_length >> blk_shift; logical_blk = fm_ext[i].fe_logical >> blk_shift; - if (logical_blk && phy_blk != expected) + if (logical_blk && phy_blk != expected) { tot_extents++; - else + } else { expected = 0; + if (!tot_extents) + tot_extents = 1; + } if (verbose) print_extent_info(&fm_ext[i], n, expected, blk_shift);