Messages in this thread Patch in this message | | | Date | Mon, 23 Oct 2006 11:23:29 +0200 | From | Thomas Zeitlhofer <> | Subject | mkdir on read-only NFS is broken in 2.6.18 |
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Hello,
there is a problem in 2.6.18/.1 when mkdir is called for an existing directory on a read-only mounted NFS filesystem.
Lets consider a server that exports the directory /export which contains the directory-tree a/b/c:
1) If /export is mounted ro and the first access to a, b, or c is mkdir, then this directory and all directories underneath become inaccessible:
client:# mount server:/export /mnt -o ro client:# mkdir /mnt/a/b mkdir: cannot create directory `/mnt/a/b': Read-only file system client:# find /mnt /mnt /mnt/a find: /mnt/a/b: No such file or directory
2) If /export is mounted ro and the first access to a, b, or c is _not_ by calling mkdir, then a following mkdir does not destroy the directory structure (and mkdir now returns EEXIST):
client:# mount server:/export /mnt -o ro client:# find /mnt /mnt /mnt/a /mnt/a/b /mnt/a/b/c client:# mkdir /mnt/a/b mkdir: cannot create directory `/mnt/a/b': File exists client:# find /mnt /mnt /mnt/a /mnt/a/b /mnt/a/b/c
3) If /export is mounted rw (although exported ro), then mkdir does not destroy the directory structure:
client:# mount server:/export /mnt -o rw client:# mkdir /mnt/a/b mkdir: cannot create directory `/mnt/a/b': Read-only file system client:# find /mnt /mnt /mnt/a /mnt/a/b /mnt/a/b/c
As a consequence of 1), autofs does not work with mountpoints on NFS (ro) because the automount daemon calls mkdir for all directories in the path to the mountpoint. This seems related to the discussion [1], and, as suggested in [1], the issue is fixed by reverting the patch:
http://kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a634904a7de0d3a0bc606f608007a34e8c05bfee;hp=ddeff520f02b92128132c282c350fa72afffb84a
So please consider this patch for the next -stable release:
diff --git a/fs/namei.c b/fs/namei.c index 432d6bc..5201d77 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1774,8 +1774,6 @@ struct dentry *lookup_create(struct name if (nd->last_type != LAST_NORM) goto fail; nd->flags &= ~LOOKUP_PARENT; - nd->flags |= LOOKUP_CREATE; - nd->intent.open.flags = O_EXCL; /* * Do the final lookup. -- [1] http://lkml.org/lkml/2006/9/22/182 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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