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ext4: More buffer head reference leaks

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After the patch I posted last week regarding buffer head ref leaks in
no-journal mode, I looked at all the code that uses buffer heads and
searched for more potential leaks.

The patch below fixes the issues I found; these can occur even when a
journal is present.

The change to inode.c fixes a double release if
ext4_journal_get_create_access() fails.

The changes to namei.c are more complicated.  add_dirent_to_buf() will
release the input buffer head EXCEPT when it returns -ENOSPC.  There are
some callers of this routine that don't always do the brelse() in the event
that -ENOSPC is returned.  Unfortunately, to put this fix into ext4_add_entry()
required capturing the return value of make_indexed_dir() and
add_dirent_to_buf().

Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Curt Wohlgemuth 2009-07-17 10:54:08 -04:00 committed by Theodore Ts'o
parent f6f50e28f0
commit 6487a9d3b5
2 changed files with 14 additions and 5 deletions
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3
fs/ext4/inode.c
View File

@ -762,8 +762,9 @@ static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
BUFFER_TRACE(bh, "call get_create_access");
err = ext4_journal_get_create_access(handle, bh);
if (err) {
/* Don't brelse(bh) here; it's done in
* ext4_journal_forget() below */
unlock_buffer(bh);
brelse(bh);
goto failed;
}

16
fs/ext4/namei.c
View File

@ -1518,8 +1518,12 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
return retval;
if (blocks == 1 && !dx_fallback &&
EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
return make_indexed_dir(handle, dentry, inode, bh);
EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
retval = make_indexed_dir(handle, dentry, inode, bh);
if (retval == -ENOSPC)
brelse(bh);
return retval;
}
brelse(bh);
}
bh = ext4_append(handle, dir, &block, &retval);
@ -1528,7 +1532,10 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
de = (struct ext4_dir_entry_2 *) bh->b_data;
de->inode = 0;
de->rec_len = ext4_rec_len_to_disk(blocksize, blocksize);
return add_dirent_to_buf(handle, dentry, inode, de, bh);
retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
if (retval == -ENOSPC)
brelse(bh);
return retval;
}
/*
@ -1657,7 +1664,8 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
if (!de)
goto cleanup;
err = add_dirent_to_buf(handle, dentry, inode, de, bh);
bh = NULL;
if (err != -ENOSPC)
bh = NULL;
goto cleanup;
journal_error: