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| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-03-21 15:37:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-03-27 11:36:36 -0700 |
| commit | 172af058996db9c3dc6230d966295ed338dc3538 (patch) | |
| tree | 6e1d9d9d11e72d252e07d8c69721f98f5478b955 | |
| parent | 144a4ea712041e818df28a2bea81431143164da8 (diff) | |
| download | lwn-172af058996db9c3dc6230d966295ed338dc3538.tar.gz lwn-172af058996db9c3dc6230d966295ed338dc3538.zip | |
NFS: Fix a hang/infinite loop in nfs_wb_page()
commit b8413f98f997bb3ed7327e6d7117e7e91ce010c3 upstream.
When one of the two waits in nfs_commit_inode() is interrupted, it
returns a non-negative value, which causes nfs_wb_page() to think
that the operation was successful causing it to busy-loop rather
than exiting.
It also causes nfs_file_fsync() to incorrectly report the file as
being successfully committed to disk.
This patch fixes both problems by ensuring that we return an error
if the attempts to wait fail.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/nfs/write.c | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 42b92d7a9cc4..b5fcbf7da6fc 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1214,13 +1214,17 @@ int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data) #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait) { + int ret; + if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags)) return 1; - if (may_wait && !out_of_line_wait_on_bit_lock(&nfsi->flags, - NFS_INO_COMMIT, nfs_wait_bit_killable, - TASK_KILLABLE)) - return 1; - return 0; + if (!may_wait) + return 0; + ret = out_of_line_wait_on_bit_lock(&nfsi->flags, + NFS_INO_COMMIT, + nfs_wait_bit_killable, + TASK_KILLABLE); + return (ret < 0) ? ret : 1; } static void nfs_commit_clear_lock(struct nfs_inode *nfsi) @@ -1396,9 +1400,10 @@ int nfs_commit_inode(struct inode *inode, int how) { LIST_HEAD(head); int may_wait = how & FLUSH_SYNC; - int res = 0; + int res; - if (!nfs_commit_set_lock(NFS_I(inode), may_wait)) + res = nfs_commit_set_lock(NFS_I(inode), may_wait); + if (res <= 0) goto out_mark_dirty; spin_lock(&inode->i_lock); res = nfs_scan_commit(inode, &head, 0, 0); @@ -1407,12 +1412,14 @@ int nfs_commit_inode(struct inode *inode, int how) int error = nfs_commit_list(inode, &head, how); if (error < 0) return error; - if (may_wait) - wait_on_bit(&NFS_I(inode)->flags, NFS_INO_COMMIT, - nfs_wait_bit_killable, - TASK_KILLABLE); - else + if (!may_wait) goto out_mark_dirty; + error = wait_on_bit(&NFS_I(inode)->flags, + NFS_INO_COMMIT, + nfs_wait_bit_killable, + TASK_KILLABLE); + if (error < 0) + return error; } else nfs_commit_clear_lock(NFS_I(inode)); return res; |