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ext4: add ext4_sb_bread() to disambiguate ENOMEM cases

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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: ac27a0ec11 ("ext4: initial copy of files from ext3")
Cc: stable@kernel.org # 2.6.19
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2018-11-25 17:20:31 -05:00
parent 2e6e902d18
commit fb265c9cb4
5 changed files with 115 additions and 94 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
fs/ext4/resize.c
View File

@@ -127,10 +127,12 @@ static int verify_group_input(struct super_block *sb,
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))
@@ -781,11 +783,11 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
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;
@@ -794,21 +796,22 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
"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;
@@ -816,18 +819,18 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
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);
@@ -837,7 +840,7 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
/* 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 *),
@@ -846,7 +849,7 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
goto exit_inode;
goto errout;
}
/*
@@ -862,7 +865,7 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
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_SB(sb)->s_cluster_bits);
@@ -871,8 +874,7 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
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);
@@ -888,15 +890,11 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
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);
@@ -916,9 +914,9 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
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);
@@ -975,9 +973,10 @@ static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
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;
}
@@ -996,9 +995,10 @@ static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
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]);