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| author | Theodore Ts'o <tytso@mit.edu> | 2021-07-18 09:15:28 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2021-07-18 11:05:20 -0400 |
| commit | 6568ba325e54a2ae1d2617c5175936c819ab4c8c (patch) | |
| tree | f773d23fe9791f6828a4c8b6f607894005524f95 | |
| parent | d0b6b64f62eff5c7545be8b71adf6fd537613a90 (diff) | |
| download | e2fsprogs-6568ba325e54a2ae1d2617c5175936c819ab4c8c.tar.gz | |
mke2fs: only try discarding a single block to test if discard works
Commit d2bfdc7ff15c ("Use punch hole as "discard" on regular files")
added a test to see if the storage device actually supports discard.
The intent was to try discarding the first block but since
io_channel_discard() interprets the offset and count arguments in
blocks, and not bytes, mke2fs was actually discarding the first 16
megabytes (when the block size is 4k). This is normally not a
problem, since most file systems are larger than that, and requests to
discard beyond the end of the block device are ignored.
However, when creating a small file system as part of a image
containing multiple partitions, the initial test discard can end up
discarding data beyond the file system being created.
Addresses-Debian-Bug: #989630
Reported-by: Josh Triplett <josh@joshtriplett.org>
Fixes: d2bfdc7ff15c ("Use punch hole as "discard" on regular files")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | misc/mke2fs.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/misc/mke2fs.c b/misc/mke2fs.c index 9fa6eaa73..5a35e9ef8 100644 --- a/misc/mke2fs.c +++ b/misc/mke2fs.c @@ -2794,7 +2794,7 @@ static int mke2fs_discard_device(ext2_filsys fs) struct ext2fs_numeric_progress_struct progress; blk64_t blocks = ext2fs_blocks_count(fs->super); blk64_t count = DISCARD_STEP_MB; - blk64_t cur; + blk64_t cur = 0; int retval = 0; /* @@ -2802,10 +2802,9 @@ static int mke2fs_discard_device(ext2_filsys fs) * we do not print numeric progress resulting in failure * afterwards. */ - retval = io_channel_discard(fs->io, 0, fs->blocksize); + retval = io_channel_discard(fs->io, 0, 1); if (retval) return retval; - cur = fs->blocksize; count *= (1024 * 1024); count /= fs->blocksize; |