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author | J. Bruce Fields <bfields@redhat.com> | 2014-12-09 11:12:26 -0500 |
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committer | J. Bruce Fields <bfields@redhat.com> | 2014-12-09 11:12:26 -0500 |
commit | 2941b0e91ba68b1f77140e556307e00616a5bb46 (patch) | |
tree | 01950b6ed12d06ebe4c39d1a2122050a9a570e93 /fs/btrfs/locking.c | |
parent | 818f2f57f20d0e9a9294180f304f34cd4e8f6066 (diff) | |
parent | 388f0c776781fe64ce951701bfe712b2182a31f2 (diff) | |
download | linux-2941b0e91ba68b1f77140e556307e00616a5bb46.tar.gz linux-2941b0e91ba68b1f77140e556307e00616a5bb46.tar.bz2 linux-2941b0e91ba68b1f77140e556307e00616a5bb46.zip |
Merge tag 'nfs-for-3.19-1' into nfsd for-3.19 branch
Mainly what I need is 860a0d9e511f "sunrpc: add some tracepoints in
svc_rqst handling functions", which subsequent server rpc patches from
jlayton depend on. I'm merging this later tag on the assumption that's
more likely to be a tested and stable point.
Diffstat (limited to 'fs/btrfs/locking.c')
-rw-r--r-- | fs/btrfs/locking.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 5665d2149249..f8229ef1b46d 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -128,6 +128,26 @@ again: } /* + * take a spinning read lock. + * returns 1 if we get the read lock and 0 if we don't + * this won't wait for blocking writers + */ +int btrfs_tree_read_lock_atomic(struct extent_buffer *eb) +{ + if (atomic_read(&eb->blocking_writers)) + return 0; + + read_lock(&eb->lock); + if (atomic_read(&eb->blocking_writers)) { + read_unlock(&eb->lock); + return 0; + } + atomic_inc(&eb->read_locks); + atomic_inc(&eb->spinning_readers); + return 1; +} + +/* * returns 1 if we get the read lock and 0 if we don't * this won't wait for blocking writers */ @@ -158,9 +178,7 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb) atomic_read(&eb->blocking_readers)) return 0; - if (!write_trylock(&eb->lock)) - return 0; - + write_lock(&eb->lock); if (atomic_read(&eb->blocking_writers) || atomic_read(&eb->blocking_readers)) { write_unlock(&eb->lock); |