The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fb265c9cb49e2074ddcdd4de99728aefdd3b3592 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o tytso@mit.edu Date: Sun, 25 Nov 2018 17:20:31 -0500 Subject: [PATCH] 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 tytso@mit.edu
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3f89d0ab08fc..b4621277e259 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2538,6 +2538,8 @@ extern int ext4_group_extend(struct super_block *sb, 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); diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index 61a9d1927817..a98bfca9c463 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -116,9 +116,9 @@ static int update_ind_extent_range(handle_t *handle, struct inode *inode, 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++) { @@ -145,9 +145,9 @@ static int update_dind_extent_range(handle_t *handle, struct inode *inode, 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++) { @@ -175,9 +175,9 @@ static int update_tind_extent_range(handle_t *handle, struct inode *inode, 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++) { @@ -224,9 +224,9 @@ static int free_dind_blocks(handle_t *handle, 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++) { @@ -254,9 +254,9 @@ static int free_tind_blocks(handle_t *handle, 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++) { @@ -382,9 +382,9 @@ static int free_ext_idx(handle_t *handle, struct inode *inode, 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) { diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index a5efee34415f..87350b642681 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -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]); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 53ff6c2a26ed..361624460431 100644 --- 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) { 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 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 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) {