From 36de928641ee48b2078d3fe9514242aaa2f92013 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 23 Aug 2014 17:47:19 -0400 Subject: [PATCH] ext4: propagate errors up to ext4_find_entry()'s callers If we run into some kind of error, such as ENOMEM, while calling ext4_getblk() or ext4_dx_find_entry(), we need to make sure this error gets propagated up to ext4_find_entry() and then to its callers. This way, transient errors such as ENOMEM can get propagated to the VFS. This is important so that the system calls return the appropriate error, and also so that in the case of ext4_lookup(), we return an error instead of a NULL inode, since that will result in a negative dentry cache entry that will stick around long past the OOM condition which caused a transient ENOMEM error. Google-Bug-Id: #17142205 Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/ext4/ext4.h | 2 +- fs/ext4/namei.c | 35 +++++++++++++++++++++++++++++++++-- 2 files changed, 34 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 5b19760b1de5..4d95c3301775 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1825,7 +1825,7 @@ ext4_group_first_block_no(struct super_block *sb, ext4_group_t group_no) /* * Special error return code only used by dx_probe() and its callers. */ -#define ERR_BAD_DX_DIR -75000 +#define ERR_BAD_DX_DIR (-(MAX_ERRNO - 1)) /* * Timeout and state flag for lazy initialization inode thread. diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index b147a67baa0d..ae7088b446d1 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1227,7 +1227,7 @@ static struct buffer_head * ext4_find_entry (struct inode *dir, buffer */ int num = 0; ext4_lblk_t nblocks; - int i, err; + int i, err = 0; int namelen; *res_dir = NULL; @@ -1264,7 +1264,11 @@ static struct buffer_head * ext4_find_entry (struct inode *dir, * return. Otherwise, fall back to doing a search the * old fashioned way. */ - if (bh || (err != ERR_BAD_DX_DIR)) + if (err == -ENOENT) + return NULL; + if (err && err != ERR_BAD_DX_DIR) + return ERR_PTR(err); + if (bh) return bh; dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, " "falling back\n")); @@ -1295,6 +1299,11 @@ restart: } num++; bh = ext4_getblk(NULL, dir, b++, 0, &err); + if (unlikely(err)) { + if (ra_max == 0) + return ERR_PTR(err); + break; + } bh_use[ra_max] = bh; if (bh) ll_rw_block(READ | REQ_META | REQ_PRIO, @@ -1417,6 +1426,8 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi return ERR_PTR(-ENAMETOOLONG); bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL); + if (IS_ERR(bh)) + return (struct dentry *) bh; inode = NULL; if (bh) { __u32 ino = le32_to_cpu(de->inode); @@ -1450,6 +1461,8 @@ struct dentry *ext4_get_parent(struct dentry *child) struct buffer_head *bh; bh = ext4_find_entry(child->d_inode, &dotdot, &de, NULL); + if (IS_ERR(bh)) + return (struct dentry *) bh; if (!bh) return ERR_PTR(-ENOENT); ino = le32_to_cpu(de->inode); @@ -2727,6 +2740,8 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry) retval = -ENOENT; bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL); + if (IS_ERR(bh)) + return PTR_ERR(bh); if (!bh) goto end_rmdir; @@ -2794,6 +2809,8 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry) retval = -ENOENT; bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL); + if (IS_ERR(bh)) + return PTR_ERR(bh); if (!bh) goto end_unlink; @@ -3121,6 +3138,8 @@ static int ext4_find_delete_entry(handle_t *handle, struct inode *dir, struct ext4_dir_entry_2 *de; bh = ext4_find_entry(dir, d_name, &de, NULL); + if (IS_ERR(bh)) + return PTR_ERR(bh); if (bh) { retval = ext4_delete_entry(handle, dir, de, bh); brelse(bh); @@ -3202,6 +3221,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, dquot_initialize(new.inode); old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL); + if (IS_ERR(old.bh)) + return PTR_ERR(old.bh); /* * Check for inode number is _not_ due to possible IO errors. * We might rmdir the source, keep it as pwd of some process @@ -3214,6 +3235,10 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, new.bh = ext4_find_entry(new.dir, &new.dentry->d_name, &new.de, &new.inlined); + if (IS_ERR(new.bh)) { + retval = PTR_ERR(new.bh); + goto end_rename; + } if (new.bh) { if (!new.inode) { brelse(new.bh); @@ -3330,6 +3355,8 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry, old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, &old.inlined); + if (IS_ERR(old.bh)) + return PTR_ERR(old.bh); /* * Check for inode number is _not_ due to possible IO errors. * We might rmdir the source, keep it as pwd of some process @@ -3342,6 +3369,10 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry, new.bh = ext4_find_entry(new.dir, &new.dentry->d_name, &new.de, &new.inlined); + if (IS_ERR(new.bh)) { + retval = PTR_ERR(new.bh); + goto end_rename; + } /* RENAME_EXCHANGE case: old *and* new must both exist */ if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino) -- 2.20.1