From fb265c9cb49e2074ddcdd4de99728aefdd3b3592 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 25 Nov 2018 17:20:31 -0500 Subject: ext4: add ext4_sb_bread() to disambiguate ENOMEM cases Today, when sb_bread() returns NULL, this can either be because of an I/O error or because the system failed to allocate the buffer. Since it's an old interface, changing would require changing many call sites. So instead we create our own ext4_sb_bread(), which also allows us to set the REQ_META flag. Also fixed a problem in the xattr code where a NULL return in a function could also mean that the xattr was not found, which could lead to the wrong error getting returned to userspace. Fixes: ac27a0ec112a ("ext4: initial copy of files from ext3") Cc: stable@kernel.org # 2.6.19 Signed-off-by: Theodore Ts'o --- fs/ext4/xattr.c | 76 +++++++++++++++++++++++++++------------------------------ 1 file changed, 36 insertions(+), 40 deletions(-) (limited to 'fs/ext4/xattr.c') diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 7643d52c776c..510c9bb7ce71 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -522,14 +522,13 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", name_index, name, buffer, (long)buffer_size); - error = -ENODATA; if (!EXT4_I(inode)->i_file_acl) - goto cleanup; + return -ENODATA; ea_idebug(inode, "reading block %llu", (unsigned long long)EXT4_I(inode)->i_file_acl); - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - if (!bh) - goto cleanup; + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return PTR_ERR(bh); ea_bdebug(bh, "b_count=%d, refcount=%d", atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); error = ext4_xattr_check_block(inode, bh); @@ -696,26 +695,23 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) ea_idebug(inode, "buffer=%p, buffer_size=%ld", buffer, (long)buffer_size); - error = 0; if (!EXT4_I(inode)->i_file_acl) - goto cleanup; + return 0; ea_idebug(inode, "reading block %llu", (unsigned long long)EXT4_I(inode)->i_file_acl); - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - error = -EIO; - if (!bh) - goto cleanup; + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return PTR_ERR(bh); ea_bdebug(bh, "b_count=%d, refcount=%d", atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); error = ext4_xattr_check_block(inode, bh); if (error) goto cleanup; ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh); - error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); - + error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, + buffer_size); cleanup: brelse(bh); - return error; } @@ -830,9 +826,9 @@ int ext4_get_inode_usage(struct inode *inode, qsize_t *usage) } if (EXT4_I(inode)->i_file_acl) { - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - if (!bh) { - ret = -EIO; + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + ret = PTR_ERR(bh); goto out; } @@ -1821,16 +1817,15 @@ ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, if (EXT4_I(inode)->i_file_acl) { /* The inode already has an extended attribute block. */ - bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); - error = -EIO; - if (!bs->bh) - goto cleanup; + bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bs->bh)) + return PTR_ERR(bs->bh); ea_bdebug(bs->bh, "b_count=%d, refcount=%d", atomic_read(&(bs->bh->b_count)), le32_to_cpu(BHDR(bs->bh)->h_refcount)); error = ext4_xattr_check_block(inode, bs->bh); if (error) - goto cleanup; + return error; /* Find the named attribute. */ bs->s.base = BHDR(bs->bh); bs->s.first = BFIRST(bs->bh); @@ -1839,13 +1834,10 @@ ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, error = xattr_find_entry(inode, &bs->s.here, bs->s.end, i->name_index, i->name, 1); if (error && error != -ENODATA) - goto cleanup; + return error; bs->s.not_found = error; } - error = 0; - -cleanup: - return error; + return 0; } static int @@ -2274,9 +2266,9 @@ static struct buffer_head *ext4_xattr_get_block(struct inode *inode) if (!EXT4_I(inode)->i_file_acl) return NULL; - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - if (!bh) - return ERR_PTR(-EIO); + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return bh; error = ext4_xattr_check_block(inode, bh); if (error) { brelse(bh); @@ -2746,10 +2738,11 @@ retry: if (EXT4_I(inode)->i_file_acl) { struct buffer_head *bh; - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - error = -EIO; - if (!bh) + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + error = PTR_ERR(bh); goto cleanup; + } error = ext4_xattr_check_block(inode, bh); if (error) { brelse(bh); @@ -2903,11 +2896,12 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, } if (EXT4_I(inode)->i_file_acl) { - bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); - if (!bh) { - EXT4_ERROR_INODE(inode, "block %llu read error", - EXT4_I(inode)->i_file_acl); - error = -EIO; + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + error = PTR_ERR(bh); + if (error == -EIO) + EXT4_ERROR_INODE(inode, "block %llu read error", + EXT4_I(inode)->i_file_acl); goto cleanup; } error = ext4_xattr_check_block(inode, bh); @@ -3060,8 +3054,10 @@ ext4_xattr_block_cache_find(struct inode *inode, while (ce) { struct buffer_head *bh; - bh = sb_bread(inode->i_sb, ce->e_value); - if (!bh) { + bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO); + if (IS_ERR(bh)) { + if (PTR_ERR(bh) == -ENOMEM) + return NULL; EXT4_ERROR_INODE(inode, "block %lu read error", (unsigned long)ce->e_value); } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { -- cgit v1.2.3