[PATCH 4.14 062/101] ext4: add ext4_sb_bread() to disambiguate ENOMEM cases
From: Greg Kroah-Hartman
Date: Mon Jan 07 2019 - 08:02:43 EST
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <tytso@xxxxxxx>
commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 upstream.
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@xxxxxxxxxx # 2.6.19
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/ext4.h | 2 +
fs/ext4/migrate.c | 36 ++++++++++++-------------
fs/ext4/resize.c | 72 +++++++++++++++++++++++++--------------------------
fs/ext4/super.c | 23 ++++++++++++++++
fs/ext4/xattr.c | 76 +++++++++++++++++++++++++-----------------------------
5 files changed, 115 insertions(+), 94 deletions(-)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2568,6 +2568,8 @@ extern int ext4_group_extend(struct supe
extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
/* super.c */
+extern struct buffer_head *ext4_sb_bread(struct super_block *sb,
+ sector_t block, int op_flags);
extern int ext4_seq_options_show(struct seq_file *seq, void *offset);
extern int ext4_calculate_overhead(struct super_block *sb);
extern void ext4_superblock_csum_set(struct super_block *sb);
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -123,9 +123,9 @@ static int update_ind_extent_range(handl
int i, retval = 0;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- bh = sb_bread(inode->i_sb, pblock);
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
@@ -152,9 +152,9 @@ static int update_dind_extent_range(hand
int i, retval = 0;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- bh = sb_bread(inode->i_sb, pblock);
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
@@ -182,9 +182,9 @@ static int update_tind_extent_range(hand
int i, retval = 0;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- bh = sb_bread(inode->i_sb, pblock);
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, pblock, 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
@@ -231,9 +231,9 @@ static int free_dind_blocks(handle_t *ha
struct buffer_head *bh;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
tmp_idata = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
@@ -261,9 +261,9 @@ static int free_tind_blocks(handle_t *ha
struct buffer_head *bh;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
- bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
tmp_idata = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
@@ -389,9 +389,9 @@ static int free_ext_idx(handle_t *handle
struct ext4_extent_header *eh;
block = ext4_idx_pblock(ix);
- bh = sb_bread(inode->i_sb, block);
- if (!bh)
- return -EIO;
+ bh = ext4_sb_bread(inode->i_sb, block, 0);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
eh = (struct ext4_extent_header *)bh->b_data;
if (eh->eh_depth != 0) {
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -127,10 +127,12 @@ static int verify_group_input(struct sup
else if (free_blocks_count < 0)
ext4_warning(sb, "Bad blocks count %u",
input->blocks_count);
- else if (!(bh = sb_bread(sb, end - 1)))
+ else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
+ err = PTR_ERR(bh);
+ bh = NULL;
ext4_warning(sb, "Cannot read last block (%llu)",
end - 1);
- else if (outside(input->block_bitmap, start, end))
+ } else if (outside(input->block_bitmap, start, end))
ext4_warning(sb, "Block bitmap not in group (block %llu)",
(unsigned long long)input->block_bitmap);
else if (outside(input->inode_bitmap, start, end))
@@ -757,11 +759,11 @@ static int add_new_gdb(handle_t *handle,
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
- struct buffer_head **o_group_desc, **n_group_desc;
- struct buffer_head *dind;
- struct buffer_head *gdb_bh;
+ struct buffer_head **o_group_desc, **n_group_desc = NULL;
+ struct buffer_head *dind = NULL;
+ struct buffer_head *gdb_bh = NULL;
int gdbackups;
- struct ext4_iloc iloc;
+ struct ext4_iloc iloc = { .bh = NULL };
__le32 *data;
int err;
@@ -770,21 +772,22 @@ static int add_new_gdb(handle_t *handle,
"EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
gdb_num);
- gdb_bh = sb_bread(sb, gdblock);
- if (!gdb_bh)
- return -EIO;
+ gdb_bh = ext4_sb_bread(sb, gdblock, 0);
+ if (IS_ERR(gdb_bh))
+ return PTR_ERR(gdb_bh);
gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
if (gdbackups < 0) {
err = gdbackups;
- goto exit_bh;
+ goto errout;
}
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
- dind = sb_bread(sb, le32_to_cpu(*data));
- if (!dind) {
- err = -EIO;
- goto exit_bh;
+ dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
+ if (IS_ERR(dind)) {
+ err = PTR_ERR(dind);
+ dind = NULL;
+ goto errout;
}
data = (__le32 *)dind->b_data;
@@ -792,18 +795,18 @@ static int add_new_gdb(handle_t *handle,
ext4_warning(sb, "new group %u GDT block %llu not reserved",
group, gdblock);
err = -EINVAL;
- goto exit_dind;
+ goto errout;
}
BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
if (unlikely(err))
- goto exit_dind;
+ goto errout;
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (unlikely(err))
- goto exit_dind;
+ goto errout;
BUFFER_TRACE(dind, "get_write_access");
err = ext4_journal_get_write_access(handle, dind);
@@ -813,7 +816,7 @@ static int add_new_gdb(handle_t *handle,
/* ext4_reserve_inode_write() gets a reference on the iloc */
err = ext4_reserve_inode_write(handle, inode, &iloc);
if (unlikely(err))
- goto exit_dind;
+ goto errout;
n_group_desc = ext4_kvmalloc((gdb_num + 1) *
sizeof(struct buffer_head *),
@@ -822,7 +825,7 @@ static int add_new_gdb(handle_t *handle,
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
- goto exit_inode;
+ goto errout;
}
/*
@@ -838,7 +841,7 @@ static int add_new_gdb(handle_t *handle,
err = ext4_handle_dirty_metadata(handle, NULL, dind);
if (unlikely(err)) {
ext4_std_error(sb, err);
- goto exit_inode;
+ goto errout;
}
inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
ext4_mark_iloc_dirty(handle, inode, &iloc);
@@ -846,8 +849,7 @@ static int add_new_gdb(handle_t *handle,
err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
if (unlikely(err)) {
ext4_std_error(sb, err);
- iloc.bh = NULL;
- goto exit_inode;
+ goto errout;
}
brelse(dind);
@@ -863,15 +865,11 @@ static int add_new_gdb(handle_t *handle,
err = ext4_handle_dirty_super(handle, sb);
if (err)
ext4_std_error(sb, err);
-
return err;
-
-exit_inode:
+errout:
kvfree(n_group_desc);
brelse(iloc.bh);
-exit_dind:
brelse(dind);
-exit_bh:
brelse(gdb_bh);
ext4_debug("leaving with error %d\n", err);
@@ -891,9 +889,9 @@ static int add_new_gdb_meta_bg(struct su
gdblock = ext4_meta_bg_first_block_no(sb, group) +
ext4_bg_has_super(sb, group);
- gdb_bh = sb_bread(sb, gdblock);
- if (!gdb_bh)
- return -EIO;
+ gdb_bh = ext4_sb_bread(sb, gdblock, 0);
+ if (IS_ERR(gdb_bh))
+ return PTR_ERR(gdb_bh);
n_group_desc = ext4_kvmalloc((gdb_num + 1) *
sizeof(struct buffer_head *),
GFP_NOFS);
@@ -949,9 +947,10 @@ static int reserve_backup_gdb(handle_t *
return -ENOMEM;
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
- dind = sb_bread(sb, le32_to_cpu(*data));
- if (!dind) {
- err = -EIO;
+ dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
+ if (IS_ERR(dind)) {
+ err = PTR_ERR(dind);
+ dind = NULL;
goto exit_free;
}
@@ -970,9 +969,10 @@ static int reserve_backup_gdb(handle_t *
err = -EINVAL;
goto exit_bh;
}
- primary[res] = sb_bread(sb, blk);
- if (!primary[res]) {
- err = -EIO;
+ primary[res] = ext4_sb_bread(sb, blk, 0);
+ if (IS_ERR(primary[res])) {
+ err = PTR_ERR(primary[res]);
+ primary[res] = NULL;
goto exit_bh;
}
gdbackups = verify_reserved_gdb(sb, group, primary[res]);
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -140,6 +140,29 @@ MODULE_ALIAS_FS("ext3");
MODULE_ALIAS("ext3");
#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
+/*
+ * This works like sb_bread() except it uses ERR_PTR for error
+ * returns. Currently with sb_bread it's impossible to distinguish
+ * between ENOMEM and EIO situations (since both result in a NULL
+ * return.
+ */
+struct buffer_head *
+ext4_sb_bread(struct super_block *sb, sector_t block, int op_flags)
+{
+ struct buffer_head *bh = sb_getblk(sb, block);
+
+ if (bh == NULL)
+ return ERR_PTR(-ENOMEM);
+ if (buffer_uptodate(bh))
+ return bh;
+ ll_rw_block(REQ_OP_READ, REQ_META | op_flags, 1, &bh);
+ wait_on_buffer(bh);
+ if (buffer_uptodate(bh))
+ return bh;
+ put_bh(bh);
+ return ERR_PTR(-EIO);
+}
+
static int ext4_verify_csum_type(struct super_block *sb,
struct ext4_super_block *es)
{
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -521,14 +521,13 @@ ext4_xattr_block_get(struct inode *inode
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);
@@ -695,26 +694,23 @@ ext4_xattr_block_list(struct dentry *den
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;
}
@@ -829,9 +825,9 @@ int ext4_get_inode_usage(struct inode *i
}
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;
}
@@ -1824,16 +1820,15 @@ ext4_xattr_block_find(struct inode *inod
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);
@@ -1842,13 +1837,10 @@ ext4_xattr_block_find(struct inode *inod
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
@@ -2277,9 +2269,9 @@ static struct buffer_head *ext4_xattr_ge
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);
@@ -2749,10 +2741,11 @@ 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);
@@ -2906,11 +2899,12 @@ int ext4_xattr_delete_inode(handle_t *ha
}
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);
@@ -3063,8 +3057,10 @@ ext4_xattr_block_cache_find(struct 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) {