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| author | Darrick J. Wong <djwong@kernel.org> | 2021-03-22 09:51:50 -0700 |
|---|---|---|
| committer | Darrick J. Wong <djwong@kernel.org> | 2021-03-24 10:36:05 -0700 |
| commit | e424aa5f547d2510f8ea1199e7b4ed8ef2d9439d (patch) | |
| tree | 5b0c117f316b0e8e442b6e285778fef6fbf3fa16 | |
| parent | 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b (diff) | |
| download | linux-e424aa5f547d2510f8ea1199e7b4ed8ef2d9439d.tar.bz2 | |
xfs: drop freeze protection when running GETFSMAP
A recent log refactoring patchset from Brian Foster relaxed fsfreeze
behavior with regards to the buffer cache -- now freeze only waits for
pending buffer IO to finish, and does not try to drain the buffer cache
LRU. As a result, fsfreeze should no longer stall indefinitely while
fsmap runs. Drop the sb_start_write calls around fsmap invocations.
While we're cleaning things, add a comment to the xfs_trans_alloc_empty
call explaining why we're running around with empty transactions.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | fs/xfs/xfs_fsmap.c | 14 |
1 files changed, 5 insertions, 9 deletions
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c index 9ce5e7d5bf8f..34f2b971ce43 100644 --- a/fs/xfs/xfs_fsmap.c +++ b/fs/xfs/xfs_fsmap.c @@ -904,14 +904,6 @@ xfs_getfsmap( info.fsmap_recs = fsmap_recs; info.head = head; - /* - * If fsmap runs concurrently with a scrub, the freeze can be delayed - * indefinitely as we walk the rmapbt and iterate over metadata - * buffers. Freeze quiesces the log (which waits for the buffer LRU to - * be emptied) and that won't happen while we're reading buffers. - */ - sb_start_write(mp->m_super); - /* For each device we support... */ for (i = 0; i < XFS_GETFSMAP_DEVS; i++) { /* Is this device within the range the user asked for? */ @@ -934,6 +926,11 @@ xfs_getfsmap( if (handlers[i].dev > head->fmh_keys[0].fmr_device) memset(&dkeys[0], 0, sizeof(struct xfs_fsmap)); + /* + * Grab an empty transaction so that we can use its recursive + * buffer locking abilities to detect cycles in the rmapbt + * without deadlocking. + */ error = xfs_trans_alloc_empty(mp, &tp); if (error) break; @@ -951,7 +948,6 @@ xfs_getfsmap( if (tp) xfs_trans_cancel(tp); - sb_end_write(mp->m_super); head->fmh_oflags = FMH_OF_DEV_T; return error; } |