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ext4: fix the number of credits needed for ext4_unlink() and ext4_rmdir()

The ext4_unlink() and ext4_rmdir() don't actually release the blocks
associated with the file/directory.  This gets done in a separate jbd2
handle called via ext4_evict_inode().  Thus, we don't need to reserve
lots of journal credits for the truncate.

Note that using too many journal credits is non-optimal because it can
leading to the journal transmit getting closed too early, before it is
strictly necessary.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
master
Theodore Ts'o 9 years ago
parent
commit
64044abf05
  1. 6
      fs/ext4/ext4_jbd2.h
  2. 4
      fs/ext4/namei.c

6
fs/ext4/ext4_jbd2.h

@ -59,12 +59,6 @@
#define EXT4_META_TRANS_BLOCKS(sb) (EXT4_XATTR_TRANS_BLOCKS + \
EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
/* Delete operations potentially hit one directory's namespace plus an
* entire inode, plus arbitrary amounts of bitmap/indirection data. Be
* generous. We can grow the delete transaction later if necessary. */
#define EXT4_DELETE_TRANS_BLOCKS(sb) (2 * EXT4_DATA_TRANS_BLOCKS(sb) + 64)
/* Define an arbitrary limit for the amount of data we will anticipate
* writing to any given transaction. For unbounded transactions such as
* write(2) and truncate(2) we can write more than this, but we always

4
fs/ext4/namei.c

@ -2748,7 +2748,7 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
goto end_rmdir;
handle = ext4_journal_start(dir, EXT4_HT_DIR,
EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
if (IS_ERR(handle)) {
retval = PTR_ERR(handle);
handle = NULL;
@ -2811,7 +2811,7 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
goto end_unlink;
handle = ext4_journal_start(dir, EXT4_HT_DIR,
EXT4_DELETE_TRANS_BLOCKS(dir->i_sb));
EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
if (IS_ERR(handle)) {
retval = PTR_ERR(handle);
handle = NULL;

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