diff options
| author | Raghavendra G <rgowdapp@redhat.com> | 2017-09-18 16:01:34 +0530 |
|---|---|---|
| committer | Amar Tumballi <amarts@redhat.com> | 2017-12-02 11:46:52 +0000 |
| commit | e785faead91f74dce7c832848f2e8f3f43bd0be5 (patch) | |
| tree | 5b46eb5fc6ee7f434e753021851167a74b9b5cc2 /xlators/cluster/dht | |
| parent | 5eea1756016c55e4138d582e34d0069744772f72 (diff) | |
cluster/dht: don't overfill the buffer in readdir(p)
Superflous dentries that cannot be fit in the buffer size provided by
kernel are thrown away by fuse-bridge. This means,
* the next readdir(p) seen by readdir-ahead would have an offset of a
dentry returned in a previous readdir(p) response. When readdir-ahead
detects non-monotonic offset it turns itself off which can result in
poor readdir performance.
* readdirp can be cpu-intensive on brick and there is no point to read
all those dentries just to be thrown away by fuse-bridge.
So, the best strategy would be to fill the buffer optimally - neither
overfill nor underfill.
Change-Id: Idb3d85dd4c08fdc4526b2df801d49e69e439ba84
BUG: 1492625
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Diffstat (limited to 'xlators/cluster/dht')
| -rw-r--r-- | xlators/cluster/dht/src/dht-common.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c index 874e263854a..ab649c08612 100644 --- a/xlators/cluster/dht/src/dht-common.c +++ b/xlators/cluster/dht/src/dht-common.c @@ -6457,6 +6457,13 @@ list: } done: + if ((op_ret == 0) && op_errno != ENOENT) { + /* remaining buffer size is not enough to hold even one + * dentry + */ + goto unwind; + } + if ((count == 0) || (local && (local->filled < local->size))) { if ((next_offset == 0) || (op_errno == ENOENT)) { next_offset = 0; @@ -6487,8 +6494,8 @@ done: STACK_WIND_COOKIE (frame, dht_readdirp_cbk, next_subvol, next_subvol, next_subvol->fops->readdirp, - local->fd, local->size, next_offset, - local->xattr); + local->fd, (local->size - local->filled), + next_offset, local->xattr); return 0; } @@ -6578,6 +6585,13 @@ dht_readdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this, } done: + if ((op_ret == 0) && op_errno != ENOENT) { + /* remaining buffer size is not enough to hold even one + * dentry + */ + goto unwind; + } + if ((count == 0) || (local && (local->filled < local->size))) { if ((op_ret <= 0) || (op_errno == ENOENT)) { next_subvol = dht_subvol_next (this, prev); @@ -6591,7 +6605,8 @@ done: STACK_WIND_COOKIE (frame, dht_readdir_cbk, next_subvol, next_subvol, next_subvol->fops->readdir, - local->fd, local->size, next_offset, NULL); + local->fd, (local->size - local->filled), + next_offset, NULL); return 0; } |