From bcdc5e019d9f525a9f181a7de642d3a9c27c7610 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Wed, 27 Sep 2006 01:50:44 -0700 Subject: [PATCH] [PATCH] autofs4 needs to force fail return revalidate For a long time now I have had a problem with not being able to return a lookup failure on an existsing directory. In autofs this corresponds to a mount failure on a autofs managed mount entry that is browsable (and so the mount point directory exists). While this problem has been present for a long time I've avoided resolving it because it was not very visible. But now that autofs v5 has "mount and expire on demand" of nested multiple mounts, such as is found when mounting an export list from a server, solving the problem cannot be avoided any longer. I've tried very hard to find a way to do this entirely within the autofs4 module but have not been able to find a satisfactory way to achieve it. So, I need to propose a change to the VFS. Signed-off-by: Ian Kent Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/autofs4/root.c | 38 ++++++++++++++++++++++++++++++-------- fs/namei.c | 50 +++++++++++++++++++++++++++++++++++--------------- 2 files changed, 65 insertions(+), 23 deletions(-) diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 5100f98..27e17f9 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -137,7 +137,9 @@ static int autofs4_dir_open(struct inode *inode, struct file *file) nd.flags = LOOKUP_DIRECTORY; ret = (dentry->d_op->d_revalidate)(dentry, &nd); - if (!ret) { + if (ret <= 0) { + if (ret < 0) + status = ret; dcache_dir_close(inode, file); goto out; } @@ -400,13 +402,23 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); int oz_mode = autofs4_oz_mode(sbi); int flags = nd ? nd->flags : 0; - int status = 0; + int status = 1; /* Pending dentry */ if (autofs4_ispending(dentry)) { - if (!oz_mode) - status = try_to_fill_dentry(dentry, flags); - return !status; + /* The daemon never causes a mount to trigger */ + if (oz_mode) + return 1; + + /* + * A zero status is success otherwise we have a + * negative error code. + */ + status = try_to_fill_dentry(dentry, flags); + if (status == 0) + return 1; + + return status; } /* Negative dentry.. invalidate if "old" */ @@ -421,9 +433,19 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) DPRINTK("dentry=%p %.*s, emptydir", dentry, dentry->d_name.len, dentry->d_name.name); spin_unlock(&dcache_lock); - if (!oz_mode) - status = try_to_fill_dentry(dentry, flags); - return !status; + /* The daemon never causes a mount to trigger */ + if (oz_mode) + return 1; + + /* + * A zero status is success otherwise we have a + * negative error code. + */ + status = try_to_fill_dentry(dentry, flags); + if (status == 0) + return 1; + + return status; } spin_unlock(&dcache_lock); diff --git a/fs/namei.c b/fs/namei.c index 6b591c0..808e4ea 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -372,6 +372,30 @@ void release_open_intent(struct nameidata *nd) fput(nd->intent.open.file); } +static inline struct dentry * +do_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + int status = dentry->d_op->d_revalidate(dentry, nd); + if (unlikely(status <= 0)) { + /* + * The dentry failed validation. + * If d_revalidate returned 0 attempt to invalidate + * the dentry otherwise d_revalidate is asking us + * to return a fail status. + */ + if (!status) { + if (!d_invalidate(dentry)) { + dput(dentry); + dentry = NULL; + } + } else { + dput(dentry); + dentry = ERR_PTR(status); + } + } + return dentry; +} + /* * Internal lookup() using the new generic dcache. * SMP-safe @@ -386,12 +410,9 @@ static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, if (!dentry) dentry = d_lookup(parent, name); - if (dentry && dentry->d_op && dentry->d_op->d_revalidate) { - if (!dentry->d_op->d_revalidate(dentry, nd) && !d_invalidate(dentry)) { - dput(dentry); - dentry = NULL; - } - } + if (dentry && dentry->d_op && dentry->d_op->d_revalidate) + dentry = do_revalidate(dentry, nd); + return dentry; } @@ -484,10 +505,9 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s */ mutex_unlock(&dir->i_mutex); if (result->d_op && result->d_op->d_revalidate) { - if (!result->d_op->d_revalidate(result, nd) && !d_invalidate(result)) { - dput(result); + result = do_revalidate(result, nd); + if (!result) result = ERR_PTR(-ENOENT); - } } return result; } @@ -767,12 +787,12 @@ need_lookup: goto done; need_revalidate: - if (dentry->d_op->d_revalidate(dentry, nd)) - goto done; - if (d_invalidate(dentry)) - goto done; - dput(dentry); - goto need_lookup; + dentry = do_revalidate(dentry, nd); + if (!dentry) + goto need_lookup; + if (IS_ERR(dentry)) + goto fail; + goto done; fail: return PTR_ERR(dentry); -- 2.7.4