ext4: add flag to ext4_has_free_blocks

This patch adds an allocation request flag to the ext4_has_free_blocks
function which enables the use of reserved blocks.  This will allow a
punch hole to proceed even if the disk is full.  Punching a hole may
require additional blocks to first split the extents.

Because ext4_has_free_blocks is a low level function, the flag needs
to be passed down through several functions listed below:

ext4_ext_insert_extent
ext4_ext_create_new_leaf
ext4_ext_grow_indepth
ext4_ext_split
ext4_ext_new_meta_block
ext4_mb_new_blocks
ext4_claim_free_blocks
ext4_has_free_blocks

[ext4 punch hole patch series 1/5 v7]

Signed-off-by: Allison Henderson <achender@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Mingming Cao <cmm@us.ibm.com>

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index b2d10da..264f694 100644 (file)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -369,7 +369,8 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
  * Check if filesystem has nblocks free & available for allocation.
  * On success return 1, return 0 on failure.
  */
-static int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
+static int ext4_has_free_blocks(struct ext4_sb_info *sbi,
+                               s64 nblocks, unsigned int flags)
 {
        s64 free_blocks, dirty_blocks, root_blocks;
        struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
@@ -393,7 +394,9 @@ static int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
        /* Hm, nope.  Are (enough) root reserved blocks available? */
        if (sbi->s_resuid == current_fsuid() ||
            ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
-           capable(CAP_SYS_RESOURCE)) {
+           capable(CAP_SYS_RESOURCE) ||
+               (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
+
                if (free_blocks >= (nblocks + dirty_blocks))
                        return 1;
        }
@@ -402,9 +405,9 @@ static int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
 }
 
 int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
-                                               s64 nblocks)
+                          s64 nblocks, unsigned int flags)
 {
-       if (ext4_has_free_blocks(sbi, nblocks)) {
+       if (ext4_has_free_blocks(sbi, nblocks, flags)) {
                percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks);
                return 0;
        } else
@@ -425,7 +428,7 @@ int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
  */
 int ext4_should_retry_alloc(struct super_block *sb, int *retries)
 {
-       if (!ext4_has_free_blocks(EXT4_SB(sb), 1) ||
+       if (!ext4_has_free_blocks(EXT4_SB(sb), 1, 0) ||
            (*retries)++ > 3 ||
            !EXT4_SB(sb)->s_journal)
                return 0;
@@ -448,7 +451,8 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
  * error stores in errp pointer
  */
 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
-               ext4_fsblk_t goal, unsigned long *count, int *errp)
+                                 ext4_fsblk_t goal, unsigned int flags,
+                                 unsigned long *count, int *errp)
 {
        struct ext4_allocation_request ar;
        ext4_fsblk_t ret;
@@ -458,6 +462,7 @@ ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
        ar.inode = inode;
        ar.goal = goal;
        ar.len = count ? *count : 1;
+       ar.flags = flags;
 
        ret = ext4_mb_new_blocks(handle, &ar, errp);
        if (count)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2bc4c21..2f310d1 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -108,7 +108,8 @@ typedef unsigned int ext4_group_t;
 #define EXT4_MB_DELALLOC_RESERVED      0x0400
 /* We are doing stream allocation */
 #define EXT4_MB_STREAM_ALLOC           0x0800
-
+/* Use reserved root blocks if needed */
+#define EXT4_MB_USE_ROOT_BLOCKS                0x1000
 
 struct ext4_allocation_request {
        /* target inode for block we're allocating */
@@ -514,6 +515,8 @@ struct ext4_new_group_data {
        /* Convert extent to initialized after IO complete */
 #define EXT4_GET_BLOCKS_IO_CONVERT_EXT         (EXT4_GET_BLOCKS_CONVERT|\
                                         EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
+       /* Punch out blocks of an extent */
+#define EXT4_GET_BLOCKS_PUNCH_OUT_EXT          0x0020
 
 /*
  * Flags used by ext4_free_blocks
@@ -1718,8 +1721,12 @@ extern int ext4_bg_has_super(struct super_block *sb, ext4_group_t group);
 extern unsigned long ext4_bg_num_gdb(struct super_block *sb,
                        ext4_group_t group);
 extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
-                       ext4_fsblk_t goal, unsigned long *count, int *errp);
-extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi, s64 nblocks);
+                                        ext4_fsblk_t goal,
+                                        unsigned int flags,
+                                        unsigned long *count,
+                                        int *errp);
+extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+                                 s64 nblocks, unsigned int flags);
 extern ext4_fsblk_t ext4_count_free_blocks(struct super_block *);
 extern void ext4_check_blocks_bitmap(struct super_block *);
 extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ca62d74..aa3a260 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -192,12 +192,13 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 static ext4_fsblk_t
 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
                        struct ext4_ext_path *path,
-                       struct ext4_extent *ex, int *err)
+                       struct ext4_extent *ex, int *err, unsigned int flags)
 {
        ext4_fsblk_t goal, newblock;
 
        goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
-       newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
+       newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
+                                       NULL, err);
        return newblock;
 }
 
@@ -792,8 +793,9 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
  * - initializes subtree
  */
 static int ext4_ext_split(handle_t *handle, struct inode *inode,
-                               struct ext4_ext_path *path,
-                               struct ext4_extent *newext, int at)
+                         unsigned int flags,
+                         struct ext4_ext_path *path,
+                         struct ext4_extent *newext, int at)
 {
        struct buffer_head *bh = NULL;
        int depth = ext_depth(inode);
@@ -847,7 +849,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
        ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
        for (a = 0; a < depth - at; a++) {
                newblock = ext4_ext_new_meta_block(handle, inode, path,
-                                                  newext, &err);
+                                                  newext, &err, flags);
                if (newblock == 0)
                        goto cleanup;
                ablocks[a] = newblock;
@@ -1056,8 +1058,9 @@ cleanup:
  *   just created block
  */
 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
-                                       struct ext4_ext_path *path,
-                                       struct ext4_extent *newext)
+                                unsigned int flags,
+                                struct ext4_ext_path *path,
+                                struct ext4_extent *newext)
 {
        struct ext4_ext_path *curp = path;
        struct ext4_extent_header *neh;
@@ -1065,7 +1068,8 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
        ext4_fsblk_t newblock;
        int err = 0;
 
-       newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
+       newblock = ext4_ext_new_meta_block(handle, inode, path,
+               newext, &err, flags);
        if (newblock == 0)
                return err;
 
@@ -1140,8 +1144,9 @@ out:
  * if no free index is found, then it requests in-depth growing.
  */
 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
-                                       struct ext4_ext_path *path,
-                                       struct ext4_extent *newext)
+                                   unsigned int flags,
+                                   struct ext4_ext_path *path,
+                                   struct ext4_extent *newext)
 {
        struct ext4_ext_path *curp;
        int depth, i, err = 0;
@@ -1161,7 +1166,7 @@ repeat:
        if (EXT_HAS_FREE_INDEX(curp)) {
                /* if we found index with free entry, then use that
                 * entry: create all needed subtree and add new leaf */
-               err = ext4_ext_split(handle, inode, path, newext, i);
+               err = ext4_ext_split(handle, inode, flags, path, newext, i);
                if (err)
                        goto out;
 
@@ -1174,7 +1179,8 @@ repeat:
                        err = PTR_ERR(path);
        } else {
                /* tree is full, time to grow in depth */
-               err = ext4_ext_grow_indepth(handle, inode, path, newext);
+               err = ext4_ext_grow_indepth(handle, inode, flags,
+                                           path, newext);
                if (err)
                        goto out;
 
@@ -1693,6 +1699,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
        int depth, len, err;
        ext4_lblk_t next;
        unsigned uninitialized = 0;
+       int flags = 0;
 
        if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
                EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
@@ -1767,7 +1774,9 @@ repeat:
         * There is no free space in the found leaf.
         * We're gonna add a new leaf in the tree.
         */
-       err = ext4_ext_create_new_leaf(handle, inode, path, newext);
+       if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
+               flags = EXT4_MB_USE_ROOT_BLOCKS;
+       err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
        if (err)
                goto cleanup;
        depth = ext_depth(inode);

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d98b033..aef864b 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -639,8 +639,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
        while (target > 0) {
                count = target;
                /* allocating blocks for indirect blocks and direct blocks */
-               current_block = ext4_new_meta_blocks(handle, inode,
-                                                       goal, &count, err);
+               current_block = ext4_new_meta_blocks(handle, inode, goal,
+                                                    0, &count, err);
                if (*err)
                        goto failed_out;
 
@@ -1930,7 +1930,7 @@ repeat:
         * We do still charge estimated metadata to the sb though;
         * we cannot afford to run out of free blocks.
         */
-       if (ext4_claim_free_blocks(sbi, md_needed + 1)) {
+       if (ext4_claim_free_blocks(sbi, md_needed + 1, 0)) {
                dquot_release_reservation_block(inode, 1);
                if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
                        yield();

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 396b01f..859f2ae 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4236,7 +4236,9 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
                 * there is enough free blocks to do block allocation
                 * and verify allocation doesn't exceed the quota limits.
                 */
-               while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
+               while (ar->len &&
+                       ext4_claim_free_blocks(sbi, ar->len, ar->flags)) {
+
                        /* let others to free the space */
                        yield();
                        ar->len = ar->len >> 1;
@@ -4246,9 +4248,15 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
                        return 0;
                }
                reserv_blks = ar->len;
-               while (ar->len && dquot_alloc_block(ar->inode, ar->len)) {
-                       ar->flags |= EXT4_MB_HINT_NOPREALLOC;
-                       ar->len--;
+               if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
+                       dquot_alloc_block_nofail(ar->inode, ar->len);
+               } else {
+                       while (ar->len &&
+                               dquot_alloc_block(ar->inode, ar->len)) {
+
+                               ar->flags |= EXT4_MB_HINT_NOPREALLOC;
+                               ar->len--;
+                       }
                }
                inquota = ar->len;
                if (ar->len == 0) {

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index b545ca1..c757adc 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -820,8 +820,8 @@ inserted:
                        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
                                goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 
-                       block = ext4_new_meta_blocks(handle, inode,
-                                                 goal, NULL, &error);
+                       block = ext4_new_meta_blocks(handle, inode, goal, 0,
+                                                    NULL, &error);
                        if (error)
                                goto cleanup;